It's already begun. I have seen multiple groups advertising no summoners on the current ex trials or just outright kicking them when they join due to ifrit and titan making encounters so much harder.

Square Enix really needs to add a way to adjust summoners visuals on an individual player level or by the time savage raids and ultimate come out summoners are going to he completely removed from the scene due to their screen wide obscurity.

Pet size all small only works if the summoner himself does it and it does not adjust the visuals at all.