Yeah I don't think MegaRay should really be banned with this insane power creep. It's simply not as good as it could be since regular ray is almost always better, as aerilate espeed is simply better than a dragon ascent. Although MegaRay could be run with aerilate ray. Revenge kill, and when you feel like being bulkier, mega evolve.
If anything, I think Deoxys should be banned. The ability to OHKO pretty much everything in the tier with the right moveset, have extremely strong priority in Extremespeed, be able to go mixed very effeciently, and being nigh impossible to revenge kill make it worthy of a ban, in my opinion. Of course things like fake out and shadow sneak beat it, but really? We really shouldn't have to run fake out or shadow sneak to even have a slight hope of beating it.