1) Absolutely nothing. :) At least not in the (many) games I have played. They just sit and wait for you to come.

2) Yes, but... You can pillage resource buildings and settlements but this is buggy at the moment. You are better off capturing them. Capturing a settlement is also buggy - "dig in" a warrior after you capture it, or it will come back.

The bandit camps do not appear to re-spawn, at least not that I've seen. So once you clear the bandits out of an area, there isn't much to raid or loot. It is difficult to heal your troops (high cost in early game), so it is a good thing there aren't many bandits running around.

1) You mean, apart from the sanitation, the medicine, education, wine, public order, irrigation, roads, the fresh-water system, and public health?

I was disappointed that that the romans weren’t more important to the game concidering how interesting they were in this period.

This is when they were using barbarians for most of their soldiers and giving land grants and whatnot.