Actually, the first trio (and the best imo) in rock history was the Cream, formed in 66. Jimi was a big fan and seemed to have formed the Experience trying to go for a Cream sound. Unfortunately Mitch Mitchell and Noel Redding were practically amateurs compared to Ginger Baker and Jack Bruce, and they couldn't keep up with Jimi a lot of the time (whereas Jack and Ginger would push Clapton to keep up with them). The Experience had amazing records, but some of their live shows are unlistenable.

And I think Hendrix did clean up his sound in 69/70, when he expressed frustration with people expecting to see guitar-humping and burning guitars at every show, and wanting to hear Purple Haze over and over again. Also, getting Billy Cox on bass seemed to tighten up his live performances. I think Hendrix's good shows are so mind-bending that they more than make up for his sloppy concerts. He really took guitar playing to levels that nobody else has been able to touch.