This was always one of the biggest annoyances for me. I didn't like that in Oblivion, all wildlife except for deer are always hostile. I really wish they would overhaul that. Perhaps giving animals like wolves and mountain lions hunting cycles or something. It would be neat if it were dangerous to travel at night with a relevantly low chance of being attacked in daylight when these animals would normally be sleeping. Skyrim obviously does have some animals that only attack when provoked (such as the mammoths), but I really hope that the more viscous wildlife isn't codded to just attack on sight.
As you suggested, the same would be great for bandits. The logical thought process for a bandit should be to size up their foe before jumping in. It would be neat if you had encounters with them where their decision to attack or not was determined based on the conversation you have with them. Like with a high enough persuasion you could talk yourself out of a fight.
Wolves should not be hostile, and they should be mostly pack animals taht hunt other animals, only attacking you if you attack them/put them into a corner. Hostile wolves should be ones diseased with rabies, etc.