Locking it to current class means you're also locking anyone else out of using all their other alternate classes to get exp or such while they run the content. Not really fair to people not using BLU.

I think the only issue I saw as much with BLU in regard to FATEs with the first arm was that BLU could sit at the spawn point outside the circle and get mobs in an area where others would have to de-sync, effectively cutting anyone else who had to sync for the FATE off from even getting to take part. That could definitely use some looking at.