I've been thinking about my post since the weekend. Gene Simmons isn't someone I would normally defend - in fact, I think he's ridiculous. But as I kept thinking about it, here's what I came up with:
I think there are (at least) two main trends in rock. One is the DIY attitude, perhaps most explicit in the punk movement, but I think it can be seen earlier on too, for instance in the various surf groups that developed, or in the skiffle movement in England which the Beatles grew out of. The other is the trend towards virtuosity. Whether the early pioneers like Jeff Beck, Eric Clapton, Jimi Hendrix, etc., or the later manifestations like Led Zeppelin, Deep Purple, or prog groups like Yes, Genesis, etc., this can also be found in jazz and fusion, where instrumental ability is prized over popularity or accessibility. In fact, couldn't Dick Dale be seen as the virtuosic manifestation of the surf movement that wasn't present in all the various groups?
Kiss definitely fall into the DIY side, or at least their earlier stuff does. They never claimed to be virtuosos. I always saw Ace Frehley as coming from the Chuck Berry school - not necessarily the best technical player but his playing was just cool.
Gene Simmons's public persona is one thing, but to claim that he's a bad player is entering the realm of taste - of course you are entitled to your opinion regarding whether or not you like him as a person or as a musician, but to make value judgements about his playing, especially in terms of rock'n'roll, is problematic at best. Of course, when they started hiring session guys during the superhero era things get fishy, but then we could get back into the Monkees debate...