they found a way to fix it today by renaming pso2.exe to pso2launcher.exe (change old launcher name to whatever)
this bypasses the launcher so you wont be able to update, but it magically fixes all lobby lag.
Pardon my french, but ive been up for 25 hours and just got back from protesting, but uh....what the actual **** did microsoft do to make THAT the fix?
Like for real, what?