Personally, I don't mind the Moria buildings. They look pretty slick, Moria only had the ruins of Khazad-Dûm anyway, so I am not sure what the point would be of adding other captured buildings or something along those lines.
I in fact regard that design as almost perfect for the purposes and role that Moria is expected to fulfill in the general faction. I too couldn't really see the point of asking for a change. This is probably one of the most unique pieces of the Edain Mod.
Regarding Smaug, I would say that 3000 resources are well enough for the leader of the faction (being this the maximum cost in the game for such prominent heroes). I assume he won't immediately be able to dispose of his full potential at the very initial stage, so that the player won't have any possibility to maximise its advantage while the dragon-hero is still at low levels. Smaug will nonetheless be an ordinary hero of the faction, meaning that he's unlikely to turn out to be unreasonably powerful (something that may instead be applied to the Balrog, given his situational nature). That said, the idea of Smaug being fully operational only from a certain amount time (or after completing some tasks, or even after buying a specific upgrade) kind of intrigues me: it might be a valuable conceptual feature to differentiate Smaug from all the other heroes of the Edain Mod (as Sauron's iconic 'death mechanism'). What worries me a bit, though, is avoiding complex and unnecessary solutions that would otherwise slow the game down and make everything too much intricate.
Nevertheless, the sort of differentiation which I referred to above could be a solid sound ground to start interesting proposals from. For example, just another hint at the matter, I'm thinking about a possible 'dual essence' of the leadership of the Misty Mountains: that is, leaving the military leadership of the faction in the Defiler's hands (the just occasion to implement his BOTFA commander-like armour?) and stressing, on the other hand, the characterisation of the winged dragon that relates to destruction, might and his own solitary existence (primary status that is already displayed by the fact that he's the Ring hero). This would thus ensure that Smaug be the real ultimate weapon of the Goblins (preserving his independent spirit), without any risk of forcing him to fit in the faction in what would be a quite unnatural role (as the military general of all); in the light of this perspective, acquiring him later in the game would go in the above-mentioned direction even more.
These are just drafted ideas that I came up with. Feel free to comment them or give other insights on alternative concepts
P.S. One of the main reasons of these suggestions of mine is exactly the wish, that I always held in high consideration, to give each leader of the factions a very unique characterisation; something even more innovative than their already much clever abilities and designs. I'm absolutely conscious of the difficulty of such bold goal, but I really believe it's a challenge worth being considered