Just have to say that I pretty much hated both Scooby-Doo movies (and I am a pretty big fan of most anything Scooby-Doo). The first one was obviously a lame parody as you said and what they did with Scrappy was WAY out of character and out of canon, but oh well- it was a parody and everybody likes to rag on this cartoon dog for some strange reason. Maybe I have a stronger temperament for these kinds of things, but I never really found him annoying. (Of course, I never had an issue with Wesley Crusher on "Star Trek: The Next Generation" or any number of similarly hated-for-no-particular good reason type characters.)
The episodes where Shaggy and Scooby had to babysit the little tyke, and they spent 6 minutes running from some muscle bound guy that Scrappy ticked off were GARBAGE, so I can agree to that much. I just picked up 13 Ghosts of Scooby-Doo last week and so far Scrappy hasn't been even slightly annoying, and actually seems to be of use. In the 3 episodes I've seen so far, he said P-p-p-puppy Power ONCE! But I still am no fan of the character. It was a gimmick, and even though Scooby has the the occasional gimmick (Either celebrity stars/cartoon crossovers, Olympic games, turning into kids, Shaggy and Scooby inheriting money), it's not really needed.
Though I STILL say the movies were based off a Pup named Scooby-Doo. Really... Freddy and Dapnhe's personalities especially. The second one was much better, though. And hey, both times at LEAST they managed to capture what made the show special.... unlike that other movie about a cartoon Dog which I refuse to mention. Didn't see the prequel ones though... there was the intention of a third one being based entirely on Pup... guess those were it.
The difference really comes out, because it's clear that the Muppets are far superior, mostly due to Jim's hard work and dedication, whereas the Kroffts' shows, they may have been entertaining, but they could've been better as far as the puppets and performances are concerned.
The 70's were a strange time for kid's television. Almost everything BUT cartoons evolved into something interesting... again, I always diss the 70's... but there was some good stuff too... Hong Kong Phooey, Groovey Goolies, Fat Albert, Pink Panther, most of the Scooby-Doo stuff.... but that was also the era where they copied Scooby and Archie relentlessly (an easy task, since Scooby was originally a COMPLETE knockoff of the Archies). But the live action shows that came out of that era... I mean, look no further than Sesame Street (sure, it started in 68, but it came together and became popular then).
It seems like when it came to Jim and the Krofts, The Krofts worked in volume, and worked exclusively on Saturday Mornings. Jim wanted prime time stuff, and as I've been saying for the past couple years, syndication was VERY good to the Muppet Show. ABC never picked anything up except for a couple specials.
And to get back to the topic, I have seen some Krofft shows and I enjoy most of them pretty well. I agree that the "Land of the Lost" movie was horrible and I don't generally like Will Ferrell. There are a few movies that I like him in- mainly "Elf" and to some degree "Kicking and Screaming". That's probably about it.
I could never get through Elf. And Kicking and Scoring seemed like a paycheck. You have to admit, early on he had some bad offers (Bewitched, but that was an idiotic idea for a film anyway). But when he came into his own, at least you can tell he had fun. Though, I still say his 1970's sports star movies are ALL the same... though, I have to admit, I liked the racing one (mainly for Sascha Baron Cohen's arrogant French twit racer, but he was funny in it too).
The movies I've seen with him I've enjoyed were Anchorman, Taledega Nights, The Producers (though he was NO Kenneth Mars), the Other Guys (brilliant film), and Megamind. And I hate to admit it, I loved him in Zoolander. I wanted to see that one where his life was actually a book being narrated, but I never did. But Blades of Glory, I watched for 20 minutes or so and gave up. I will say this, his films have an audience, they speak to people, and they seems like they generally deserve to get made (LOTL would have sucked no matter who was in them)... unlike Rob Schnider. And Will is still less annoying than Adam Sandler. I liked that cat's earlier films, but his recent ones... shudder shudder.