Mechanically on the roll of a lucky number, the bard got a chance to steal someone else's luck points for their own (think HP drain). It wasn't automatic, but it was useful. The problem became that it was too infrequent for it to ever be to the forefront. It required both the luck of the roll and that the opponent had luck points.
The second problem was the roll of a lucky number also often coincided with gaining an "opportunity attack". This required the use of creative brainpower already, and after the combination of the attack and the opportunity attack would drain the target of luck points before wit could work.
The solution came with the immense satisfaction that came through the priest power "exorcism". This allowed a priest to physically harm supernatural creatures through social conflict as if it was physical damage. It was reliable but not overpowering. And people seemed to love it.
Thus I modelled Wit after exorcism. A bard with this power could now launch social conflict attacks as if they were physical attacks against an opponent. As with exorcism there were criteria: The attacks could only damage luck points and the bard must be in physical combat with the opponent, as the opponent's target. The bard could thus not sit on the sidelines and heckle, nor could the bard taunt an ogre to death, or in any way physically harm someone through speech alone. This seems to be going well in testing as it allows the bard to participate in battles, much as a warriors "trademark item" may give him the credibility to participate in social conflicts in a limited scope.
Making sure everyone at the table has something to do is a prime concern.