The problem is probably this perception that Brd is a "DPS+Support" class. There is no such class in the game. There is: Tank, DPS, Heal. That's it!

Maybe the solution is to give the other DPS jobs some additional "support" abilities so that they are perceived the same as bard in that area (many believe they already are but perception is reality to most). Then, increase the dmg from BRD to be on par with the other DPS jobs and there will be complete parity.

As far as the loss of mobility is concerned, that's not a big issue IMO (as long as the dmg is balanced, which it currently isn't), except that you are forcing players to change their fundamental play style when they hit the level at which they get WM. No other job has such a dramatic shift.