On Bribing:

Bribing actually appears to have been a frequent feature of the ancient warfare. I remember reading about a Numidian general/prince who while being a Roman ally upset them considerably. Upon Senate's orders he was escorted to Rome to face a Senate trial. Nonetheless, he got away by bribing the SENATE... Even more, once an army was dispatched to take care of him in his home town: he bribed the whole lot at his city gates to leave him alone...

Probably, within the game, the AI should be more prone to use bribing... Of course, only if it's profitable to the respective faction. Imagine how upsetting it would be to lose the nice stack you just built to attack someones empire. So far, i've seen only a few cases when an AI agent attempts to bribe my armies: and, unless it was a family member strolling alone, it never tried to bribe the small captain lead stacks in transition.

Also, in my opinion, the likelihood of a bribe being accepted should be toned down. Other than that: it could stay as it is.