Heh ... it's totally possible that two Tiers 5s gestalted, are still Tier 5.
+
=
I was thinking about what to call the stuff above Tier 1.
It can keep going, but with obvious discernible levels.
Like
comfortably and easily 2x actions and 2x resources = A-tier
or
comfortably and easily 5x actions and 5x resources = B-tier
comfortably and easily 10x actions and 10x resources = C-tier
Leadership isn't A-tier but it's close.
Thrallherd is A-tier but it's not from levels 1 to 10
Gestalt tier 1s can be A-tier but need an obvious action adder.
Beholder Mage and Planar Shepherd feel kinda B-tier without any thinking.
etc ...