Yup, very few quests, esp when compared to say Oblivion. As for Dwemer Ruins, you would NOT like the mod. The Dark Roads is pretty much dwemer and falmer based.
I have only hazy memories of the Mages Guild on Oblivion. Had the game on the 360 and a RROD meant that I was halfway through the Mages Guild quests for about two years until I finally got a replacement >.<
One second I was learning to create wards... Next minute, I am sent to save the world, and then crowned arch Mage.. All in three or four quests. Boring.
Was it really only three or four quests? I though it was more, but maybe I'm including side-quests? Anyway those Dwemer ruins were absolutely endless. I really do feel like the lengthiest dungeons I've come across in Skyrim seemed to have been the ones I was thrown into by the College. That was the main sticking point for me. It felt lengthy, even if it was only a handful of quests.