Now that flash is here, maybe you can put back the old Assault-modes and allow players to filter out 1 mode. So basically, you can skip 1 mode you dislike.
(Yes I would put Clash on remove immediately) 
Would be nice to be able to choose game mode in QP.
But I think they are too afraid of queue times to do this…
Well they kinda did the same with battlegrounds in WoW; you could blacklist 2 battlegrounds and that was great.
I preferred be able to choose the gamemode. But be able to choose one game mode that we don’t want would be welcomed too. For Clash is to early to have an opinion, but at least with time I started disliking Flashpoint
Clash is the perfect quick play mode.
If you play the right comp, match is over in under 3 minutes.
In theory it shouldn’t impact queues. But it would be an increase in game time.
It could find lobby, then enter a map ban phase, then it can randomly pick after that.
Problem would be that phase would need to be a quick turn around, like 20-30 seconds. Is that enough time for certain players to find the maps they don’t want. They wouldn’t want it to impact the general quick, casual nature of quick play.