+6 at 90 is horrible. An increase, a negligible increase.

A higher increase would fit better for that ring slot. Otherwise as new updates come about, eventually Raja's will be replaced by whatever comes out. At current rate, HQ Rings have not been released for the last tier of Synergy Rings which give +7, though they were seen in dat files. Which implies those rings, at that level would be +8 Stat. The way rings have been released recently as the level cap increased, it went from +6, to +7 rather quickly. It'd be no surprise to see +9-10 as a norm by 100.