I kind of chuckled when I saw the title of this thread...
Watching Rio I was thinking to myself that Robin was probably the weaker of the 3 on at least his solos, and I was really surprised by that, because on May 12th, Robin was fit to be tied.
None of the guitar players could be dubbed "obsolete" though or else Axl wouldn't even have them there.
Im sure Axl has other things he could spend his money on...