alt Hacker NewsFrets are already on equal temperament on the vast majority of mainstream guitars; you're not getting away from equal temperament unless all you play is open strings, like a koto/harp.
If octaves are perfect with one string in between, the in between string can be slightly detuned from equal temperament to provide a clean fifth, free of beats. Then it also provides a clean fourth up to the octave. That's a useful thing that will make certain chords sound good.
That’s not very helpful. You can only do that one string, and it breaks the perfect octave starting on the detuned string. As soon as you also try to detune the next string up, you break the octave you started from. This is a house of cards idea that falls apart immediately.