Would you agree with the view that most powers are relatively underwhelming once you you level up the good guns?
Depends how you mean by most powers are relatively underwhelming,
I would argue that powers do not have the potential that weapons do. IE you have active abilities, passive abilities, gear, weapon consumable, ammo consumable, and gun mods 10 levels. Whereas powers you have Passive, Levels (which are incredibly easy to get), limited gear, limited mods.
So yes I think that the upper echelon for guns is indeed higher and left powers behind (mostly for more experienced players).
I personally always saw powers as a means for players to get an incredible increase in power early on,
Basically the concept of multiple balance curves, over time.
Powers were first to give you a boost
Weapon Mods/Common Weapons were Second
Gold Weapons, and gear were Third
UR were fourth
Dont get me wrong I think there are powers that were left behind with power creep