Scooby-Doo is clearly a very lucrative property, but I think it's got to the point where it's been overly abused now. At least when there's something new of Batman or Superman, people pay attention, with Scooby-Doo, it's more out of nostalgia, and then they go about their day.
I'll start at the bottom of this franchise with companies who have nothing but money on the brain and in their eyes: The comics. DC Comics have clearly no interest in doing quality work except for the Jim Lee pushed Scooby Apocalypse. Otherwise, there's Scooby-Doo, Where Are You? and Scooby-Doo! Team-Up (and if Jim Lee was such a fan, then maybe you'd think they'd push for higher quality comics all around?). Team-Up is an ambitious crossover of DC superheroes and Hanna-Barbera guests, and while it got off to a great start, it has started to suffer from the stock images (that the Where Are You? comics are bombarded with) that either save time or money, or both. Scooby makes money, but money needs to be put in these comics, so doing it the stock way, would be a lot cheaper. If you look at the ones from Gold Key Comics and Charlton Comics, they're really quite terrible, but the point of why I'm bringing them up is that they had freedom with what to do, or at least the artists were given the freedom. And Archie Comics could be quite as terrible, characters weren't spot on and the art was insanely awful, but they had heart. 20 years ago, even 10 years ago, DC had the heart, the look, everything, but they've decided (presumably with WB's input as well) that stock, to make it look like the cartoon 100%, even if all the integrity is lost, is the better way to go. You can do art and writing with freedom, and still make it believable to the characters, but the company money banks have lost sight of this. Why should I complain? We're getting more Scooby, but it doesn't mean I should pay for second best quality. All of the art you see on DC, can be found on merchandise from Scholastic and Hallmark, which is how wasteful DC is being.
Now onto the animation side, with Mystery Incorporated. While ambitious, it was nothing more than a rip-off of everything the team had seen. I like it, I don't completely hate it, but at the end of day, it's not really at the standards you'd expect. It got a lot of fans out of the non-Scooby stuff, which, yes, you want to have a broad appeal, but not to the point where you lose the point of the characters.
Be Cool, Scooby-Doo! had a lot of work put into, but it didn't get the full attention it deserved from Cartoon Network, who let it down, and as did Boomerang. It was supposed to air on Boomerang, then CN apparently liked it so much, they wanted to air it, but burned through the first 10 episodes that were available, and then it just fell flat after that. Even if it did gain interest once all 52 episodes are aired, it likely won't get a third season, just like SDMI didn't get a third season.
The whole property needs a break, so when it's returned to there's energy and excitement, as with Scooby-Doo on Zombie Island, which had no studio interference. This only happened because it was on a break of new material, only with the new Johnny Bravo crossover. Apart from that, there was only reruns from Scooby-Doo, Where Are You! (maybe The New Scooby-Doo Movies, I'm not sure), and that's where the attention and enthusiasm came from to do Scooby-Doo on Zombie Island, which was enough of a success to get sequels. But now there's no passion, or at least there's really not much passion from the final result. There's some I really like in the those few years to follow (except Scooby-Doo! and the Legend of the Vampire and Scooby-Doo! and the Monster of Mexico, they're not the best, in fact, they're pretty much franchise killer, but it's still profitable, so it didn't end). Scooby-Doo! and the Loch Ness Monster, in my opinion, saved the franchise (not that it needed it, because as I said, it's profitable, so it didn't exactly need saving, maybe not from a financial point of view, but definitely from an artistic point of view, from both the writing and animation. The ones that I said amounted to franchise killers, were very boring "Remember the old show?" art). They're all very okay after that, and then a whole new set of people come on for Scooby-Doo! Abracadabra-Doo.
While I wasn't really into the Fraphne subplot. I mean, for goodness sake, this has been done to death. I'm sure some president or someone else in power, or even some boot licker at Warner Bros. Animation keeps on bringing this up, and this gets a resounding approval. But if they're going to pander to the few people that like this, then why not pander to the Scrappy fans, or the Scooby Dum fans. I guess because that really would be a BAD idea, even worse than the turd story lines they constantly push of Fred and Daphne (which had some good qualities in Scooby-Doo! Stage Fright, but ultimately fell flat in a mid credits scene, that has never been done before, and because the people at WBA just want to SCREW around with us). So, anyway, we got a new lease on life from Tony Cervone and Spike Brandt who produced and directed, who did a few others after that. Paul Dini and Alan Burnett, who did some 80's stuff, who were still fresh enough to bring something new and watchable, along with Misty Lee. Cervone and Brandt wanted the old look back, but not the same blandness that those franchise killer films did. But even then, the art is debatable, since it's just clearly for nostalgia and has gotten old real quick. Daphne was given a tan and looks even more shallow than before. Scooby-Doo! Music of the Vampire and Big Top Scooby-Doo! are good Daphne moments, but apart from that she's been nothing more than a glorified cheerleader, which has its good and bad moments. In the end. #14 was a good start to the next chapter in the franchise, before it started to go down hill again. But I don't think the masses would probably notice, because Scooby is just Scooby.
Cervone and Brandt continued to do a few more, until for whatever reason, they left (I think they were still doing what was left of SDMI, though). When they left, WB clearly liked the look they brought on, and got the people left behind, and the new people hired to continue that look. But Scooby is all about change, and it's really time for a change.
So, in the recent years the break that needs to happen, is because of studio pushed "gems", such as Scooby-Doo! WrestleMania Mystery, Scooby-Doo! and KISS: Rock and Roll Mystery, and Scooby-Doo! and WWE: Curse of the Speed Demon. The last one of those is okay, but they've still been pushed in with WWE and KISS, neither of which fit, or at least not in the way it could have (how it could fit, I don't know, which pretty much equals to not being worth the time to make in the end). The first two of those movies pushed Fraphne to its burned out limits. They brought Cervone and Brandt back for the KISS one, and with Cervone being a KISS fan, I think to everyone that may have made sense. Cervone and Brandt made the TV version of Duck Dodgers then made The Looney Tunes Show, which are great reimaginings of the characters, but what they've done to Scooby has been either okay, great, or very, very, very bad. No matter how cool it is you think bringing Scooby and KISS together is, it's just not worth the risk.
The New Scooby-Doo Movies and several celebrity guests in What's New, Scooby-Doo?, while odd and maybe pointless at times (especially the former), I don't think ever forgot the essences of Scooby, Shaggy, Fred, Daphne, and Velma, the stars of the shows.
And now we've got LEGO Scooby-Doo! cartoons, while okay, I don't think they pack the punch that they could be doing. I think the web shorts, which use the figures through stop-motion, are more enjoyable than the longer, CGI-animated products are.
So, I think the franchise has gotten very tiresome and is just a way of cashing in more money for WB than an actual real attempt to make quality productions, that have been and still could be.
Next, will be the big screen movie of 2020, which will be directed by Cervone and Dax Sheppard. I mean, this is something they want to start a cinematic universe, with other Hanna-Barbera entities (because the likes of Laff-a-Lympics made so much sense already). I'm sure having Dax Sheppard will really get that going. It's all about the money.