Just to set the record straight, I've been going Barbless way before the ban.

I started while stream fishing here in MI for trout. I noticed that my single hook spinners/lures were easier on the trout and my fingers.

That led too mashing down the barbs. I replace all my treble hooks with single barbless hooks when possible.

I don't think there's conclusive evidence, one way or the other on the barbless issue?
A lot of it has too do with how the angler catches /releases his catch, with or without barbs.  

I don't have a problem with the ban, but its' still a slippery slope.
By outlawing barbs, your giving the nut-jobs further ammo for their cause. They'll say it's to cause the fish less "pain", increase mortality.
If they can "feel" pain, then in their view, sport fishing is a form of " animal cruelty" and should be outlawed.

Sure sportsmen put a lot of money into the tax kitty, but their still a minority of voters. The people making the game laws are for the most part either elected or appointed by an elected official.  All politicians pay attention to the polls, science and logic be damned.

I'd rather see the sportsmen and local people who know the land and have a vested interest in keeping it cared for, staying ahead of the nut-job curve by being pro-active rather than re-active.