Skyrim so far has been an amazing game. However along with the other elder scrolls games one of my main thoughts and wonders have been about the dwarfs. A lot of their cities remain the the world of cyrodiil but it never really gives you a full explanation about the race. As you can explore what remains of there formor glory and wear their armours, make them even aswell as their weapons it's still hard to believe there isn't one remaining dwarf left. The reason I say this is because how can blacksmiths and youself create items that the instructions for was probably lost along with the race. Therefor it stands to reason to be able to create such items one has to be shown how to do so. Not even the best of blacksmiths would have any idea of how to make a perfect set of armour or weaponary as you find throughout the world.
Anyway back to the expansion pack part of this which was my main topic why not make one explaining about the lost race or even add a few of them in there and do something like a flash back to the dwarf era, this would give a better perspective on the whole area of the dwarfs.
I might be going abit to far out here but why not add a small surving group of dwarfs into an expansion pack or dlc.

No. I will leave it at that. The Dwemer should never make a full blown return to TES. If you want to learn more about the Dwemer you should play Morrowind. It isn't obvious but it tells you A LOT about the Dwemer and even how they disappeared and kind of where they went.