Yes, the Hendrix bands mattered--Mitch Mitchell was (at least) one of the greatest rock drummers ever and his work with JH (listen to the live stuff) is very good. Probably the best trio was with Billy Cox on bass.
Bands where U say
I've yet to see a thread like this so here goes: what bands come to mind where you think what might have been? Perhaps they disbanded too soon, or a member or members died, leaving unrealized potential. I often wonder what would have come of the pretenders had honeyman-scott and farndon not bought the farm. I could list others, but would rather hear from you.