Actually, Doug Ingle of Iron Butterfly played not a Hammond organ, but a Farfisa, same as Ray Manzarek of the doors (lower case their choice, not my mistake). That’s one reason they both sound so cheezy ;-) . The drum solo in "In-A-Gadda-Da-Vida" a good one? Ay carumba!
Forgive me, but I’m not positive what constitutes "Classic Rock". Is it the Rock music that was played on the radio in the 70’s? If so, I’m not sick of it because I never liked or listened to it when it was new. I’m not special in that way; all the musicians I have ever known felt and feel the same way. There are of course exceptions, such as Fleetwood Mac and a few others. I do know what constitutes "Arena Rock" (1980’s, right?), and find that "music" particularly unlistenable. To each his own!
A lot of Rock music is so 1-dimensional that it doesn't stand up well to repeated listenings, and so trendy that it doesn't age well. Music that is immediately assessable tends to wear out its' welcome sooner than does that which takes numerous listenings to fully absorb and appreciate. I won't mention any names here, as the distinction between the two groups are very personal. I have some albums which are still revealing themselves to me, even after many, many listenings. Classical music (and to a lesser extent, imo, Jazz) is inherently music of that sort.