I think the problem is that we have a different idea of what counts as a problem.
Have I ever had a problem finishing some random pug dungeon because I've ended up with condition specced players? Not really.
Have I ever noticed a run slowed down because I've ended up with condition specced players? Yes, definitely, to the point where I do not invite condition specced players if I have a choice. If I'm gonna go do all the paths to some dungeon in one go for farm, I want it to go with speed and if I get a bunch of whispers to the LFM spam I'm really not going to invite a necro who probably can't do shit anyway. My warrior with a super pumped crit rate and a crit bleed trait that I really can't get rid of keeps up a good bunch of terrible damage bleeds already taking up space and then add to that all the random conditions that the other not really condition specced players apply.