Who said I was doing 550-600? The highest recorded BLM DPS right now on T13
is 515.2, and that is under extreme optimal scenarios (NIN, BRD, 126 ilvl, dreadwyrm weapon).
I currently do around 462-463, and I think that's pretty good considering my gear, how bad you think Summoner is, the fact I don't have a Ninja, my non-dreadwyrm weapon, etc. Certainly doesn't seem bad. Definitely not unplayable as many users in this thread are suggesting.
Why are you whining about Summoner if you have Summoners that do good DPS in T13? You're confusing, not going to bother taking this any further with you.