Aside from the obvious additional quests/hair/clothes etc I would like to see:

Additional Rooms: Building Tool aside (which I think should also be in the Expack) I would love if it you could spend RP on adding additional "utility" rooms to various building, like say a Dungeon to your Castle or a Observatory to your Wizard's Tower.

Free Building Placement: Being able to place buildings in spots other then their default, such as having your Wizard's Tower where your Knight's Barraks is normally or having your Physician’s Clinic in the Town Square. (With obvious limitations i.e the castle being unmovable, the Spy Quarters having to be attached to the Castle, the Tavern having to be in the Town Square etc.)

Landscape Choice/Architecture: Someone mentioned this in the "things TSM is lacking" page, but having a choice of different "lands" (i.e desert, tundra, islands, mountain) in which to start your kingdom with reskinned building exteriors to match (such as having Egyptian style architecture on the outside of your caste with all the interior furnishings still under your control) would be a huge step to custamability IMO.

There’s more but those are the big ones for me, what about you guys?

Something else to whittle besides a horse. Oh, and a spinning wheel that works.

I think I've seen horses/quicker form of transport nearly everywhere. More different quests would also be good.

Someone posted as a joke tiny unicorns/dragons as pets, which made me fall off my chair laughing.

I was thinking that this would be both easy and neat: I don't so much care if the buildings always are in the same place, although the buildings are so small that it's tough to add furniture, etc. But I noticed that when you choose a throne room, you're really choosing an entirely different castle layout. I would love it if they could do that for all the other buildings!

And of course they should fix the things they busted in the last patch. But I do hope they really do an expansion. I love this game.

Less text, more pretty pixel people doing things. World Adventures showed us that it is possible to integrate exploration-driven adventure quests with regular gameplay so I don't see why locations like the forest and the cave can't be opened up. I wouldn't even mind having additional loading screens if we can get separate cave/forest/village/foreign territories mini maps. My biggest issue with TSM is that 90% of the action happens offscreen, but this can be remedied with the addition of WA-type obstacle courses.

A better combat system. I love the blacksmith profession but there's really no point in having all this fancy schmancy endgame equipment if Knighty McKnighterson is pretty much guaranteed to win every duel once he reaches level 7. Like, I'm not looking to play WoW here, it'd just be nice if we can customize our heroes' stats a bit more. And make them fight creatures other than Sims (e.g. the wild boars that are always mauling my Sims in the forest).

And yeah, like others have said, non-identical kingdoms and/or buildings. Even a choice between, say, three kingdom themes would be amazing, similar to how you can play different Sims 3 neighbourhoods.

YES! I hate that EA puts getting rid of loading screens above improving gameplay. Why would anyone care about having to wait a few minutes if they get a genuinely better gaming experience? I mean, honestly..

I would like to see some further customization of the buildings/land as well. I'm not really a builder, so not having that aspect has never bothered me, but I certainly do get tired of looking at the same thing kingdom after kingdom. Any amount of variety would be welcome.

I'd really like proper aging to be implemented. I guess I understand why they ultimately decided not to include it, but I don't see why it can't at least be an option.

Yes to everything you guys have mentioned, especially new locations. I also want new heroes! I want a peasant hero, like a farmer maybe, who then gets to leave his or her humdrum life behind and go on grand adventures. Pirates would be pretty awesome, too, and I'm always game for more fantasy elements.

Aging is really all I want...

I would really like farmers. Not just one even maybe. Or just profession less controllable Sims. Imagine, your making a theme kingdom and after making all of the ones that make sense, the only space left for you male main sim's "true love" (or whatever) is blacksmith. How many story's have female blacksmiths?

I think that the entire household of a heroes building should be controlled when that hero is used for a mission. That way you can let spouses and children help out. It could maybe also allow a second hero of the same type to take residence. This hero could help out with the quest, but only the hero selected for the quest would get the experience and other rewards from it.

Some new quests could even require two heroes of the same type, expanding the possibilities for quests with a lot of new options.

Some examples of such quests:
-both your bards needing to perform a great play. Plays are done by two sims after all. One bard could write it while the other could promote the upcoming play before they eventually star in the play together.
-Blacksmith rivalry. Both need to forge different items of the player's choice and present them to a jury. The jury could have odd preferences though making it difficult to predict the outcome. The winner could gain a reward.
-A peteran priest having converted to jacobism. The other peteran priest would need to convert his fellow priest back, a jacoban priest could play a secondary role in this who wants to keep his new follower. A jacoban version of this quest could also be available.
-Knightly tournament. Both knights could sign up for a tournament. Their rivalry could be either friendly or hostile, depending on the player's actions. Both could compete for the hand of a princess in marriage.
-Merchant dispute. The two merchants could have an arguement about what to invest in and could ask the monarch for help.
-Cursed Physician. One physician could be cursed, whatever he/she tries to do has negative effects and it is up to the other physician to cure the cursed physician, maybe with a little help from a wizard or priest.
-Undercover spy. Both spies could cooperate on a quest, with one luring out an enemy while wearing a disguise and being placed in danger, and the other being relied on to keep an eye on the spy and come to the resque when needed.

On a side note, it should be possible to let the two heroes be related, like two merchant brothers running a family business.

Some of what your asking for can be accomplished with cheats. Shift+leftclick set profession on sim and add to active household. Voila! you have 2 merchants living in the same house. Shift+rightclick add sim to active quest; though sometimes you have to click more than one time to actually capture them.
I would rather they add space for additional markets and blacksmith shops so multiple heroes don't have to all crowd into the same tiny space.
And some variety in buildings...if you don't import your kingdom into the next ambition you get to build a whole new kingdom....which looks exactly like the old one.

Variety and customization are a large part of what I play the Sims for, so more variety of buildings would be great. New classes would good, but really I'd like more mod support, and the ability for players to make quests.

I'd also like sword fighters to be able to kill non-sword fighters (though if there is witnesses it might be considered a pit-beast level crime) and wizards to be able to nuke someone to death (again if witnesses, you might be saying hi to the constable and the pit beast.)

the ability to run would've been nice. although that would've probably highlighted how small your kingdom is compared to any of the basic TS3 neighborhoods.and like others have said, aging would've been fun as well. i also agree with the ability to choose landscape settings (island, desert, etc).

also, the ability to merge pre-made building structures like lego blocks and change their sizes to adjust the rooms contained within each block. could maintain the 'medieval' look while at the same time allowing more build freedom. (ie: merge a tower block with a castle block, etc..) someone else might've mentioned something similar..

anyway, i would like to point out some features from other similar games that i liked, which might work great on future Sims Medieval versions..

1)Black&White 2: the feature i like about this game is how the merging of sim-type world building tools and RTS elements created a very dynamic gaming environment. basically, you create a kingdom, strengthen your beast, create an army, and conquer your enemy. it should've been something truly epic. save for Peter Molyneux's tragic sense of juvenile comedy.. (not my cup of coffee) although the AI for the giant beast is amazing as well.

relevance: Sims Medieval would be so awesome if you can actually build a kickass army for your kingdom and then send them forth to conquer other kingdoms. 'coz let's face it. medieval settings without medieval warfare, just doesn't sound 'medieval' to me. also, if you played black&white, the growth of your city/kingdom is very dynamic and interactive. you could even say that it felt like it's growth was almost organic. the population also tends to voice out their needs and aspirations to urge you to build particular structures or perform certain tasks to stimulate further growth. such as assigning disciples, urban planning, etc..

2)Majesty 2: the feature i like about this game is that you don't directly control your heroes. instead, you assign bounties to a particular task and then heroes that are available and capable of achieving the task will try to achieve it on their own volition.

relevance: this feature could allow you to control your monarch just as you normally do, while you send your other heroes to accomplish tasks that you assigned, autonomously via bounties. (ie: if you create a bounty for a doomsword, then blacksmith will try it's best to build one for you. if you create a bounty for patrol, then the knight and the spy will patrol for you on demand, etc..) this would save the player from the menial task of micromanaging multiple heroes at the same time.

3)Empire: Total War: this is a 4x game (explore, expand, exploit, and exterminate) which combines strategy with tactics of an RTS.

relevance: the annexed kingdoms could be handled similar to how they handled it in Total War. you can add garrisons, assign governors, add structures to improve it, and try to keep your annexed population happy. in Sims Medieval. none of the kingdoms seem to be at war. which seems very unrealistic..

4)Spore: the feature i like about this one is it's massive scale.

relevance: if the guys who made spore can create that massive amount of planets and solar systems and cram it into a single game. imagine what a Sims Medieval game would be like if similar technology could be applied to rewrite it's engine and allow massive scalability, even for just a single world. it's mind boggling.

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anyway, even the games i mentioned have their own faults and limitations.

but still, i think that since Sims Medieval was EA's attempt to attract more male gamers into their Sims franchise.
(the artwork for the intro somehow reminded me of Jim Lee's artstyle.. lol..)

they should probably look more into RTS, and 4x games for inspiration as well.