I won't comment on Joe's importance to the band, but when people speak of "harder edge" I assume that they are talking about live performances (??), as Hotel California is IMO the "slickest" album they ever made. When I want hard edge, Hotel California is not the album I go for. I don't consider Life In The Fast Lane, or Victim Of Love, "hard". The former is very disciplined and sophisticated rock to my ears and the chorus in the latter is pure pop.
I have always wondered about this "edge"/"hard"/"rock" thing when it come to the Eagles. It's obvious that their guitar department was much better later on when it comes to rock music, but IMO if I take their records and put Out Of Control (original lineup) and Good Day In Hell (original lineup plus "Fingers" on slide), they are harder and "edgier" than those HC tracks I mentioned. In Out Of Control the band is really rocking IMO and the rhythm guitars (at least Glenn's) sound dirty.
Something like Earlybird has much more edge IMO than anything on HC. So, once again, I assume that people are talking more about
live performances when they say that the Eagles gained "harder rock edge" (or whatever the term is
). Am I right?