I grew up seeing both "Scooby-Doo, Where Are You?" and the various spin-off series in reruns as a kid as well as the first run of "A Pup Named Scooby-Doo" and I've always loved all of them. But while "A Pup Named Scooby-Doo" is definitely a bit of a parody, it still maintains the right amount of respect for the original series that the movies were very much lacking. (Well, the 2 theatrical movies, that is. The new direct-to-video production is actually very good. I'm looking forward to the follow up to that.)

Tiny Toon Adventures is its own thing and I love watching that one too. Though Bugs Bunny, Elmer Fudd, Daffy Duck and the rest of the gang were around sometimes, it doesn't seem like they were really there that much through most of the latter part of the series- like you didn't really have to have them around to enjoy the junior versions of them.
I've only seen the one episode of Yo Yogi! I've got on VHS. I can't recall if I ever watched this one as a kid. I don't think it's quite so terrible, but it's not necessarily my favorite Yogi series either. I like Yogi's Treasure Hunt and Yogi's Gang better.