Even Gene and Paul have said that they were never great musicians, which was part of the reason for all of the smoke and mirrors that started out small, and got to the scale that they have been for decades. Basic rock riffs indeed, but as mreaves noted they know how to market themselves.
Kiss is always a good live show. Always entertaining, and that's what they are. Entertainers. If you have never seen them live, try and catch them on this "final" tour. It's a good time.