In my opinion a difference must also be made between battles on open field and sieges. The passiveness on open ground has been greatly reduced (!). The passiveness in sieges still is there.
I have besieged about ten settlements since the patch. Everytime I was successfull with the following tactic.

1. Shoot a hole into their walls
2. The AI will send troops to that hole and keep them there.
3. March some crossbow-units in front of that hole.
4. Line them up.
5. Ready
6. Aim
7. Fire!

So far, the AI never attacked my by moving thorugh the hole, even if my crossbows were NOT backed up by some other unit.