I have yet to finish it and I'm anxious to know. Will repairs actually happen like the Jarls say, or is it just idle dialogue, and will the damaged homes and stuff always be wrecked?

I joined with the imperials on my first character after seeing how Ulfric didn't care about the dunmer in Windhelm.

Talking to the dunmer after the civil war, they said that things were looking better, but I didn't see any tangible improvements.

Windhelm will get repaired, but the post-battle rubbish is still strewn across Whiterun. I blame the Stormcloak invaders.