Something tells me they wanted to channel Seth MacFarline when designing the characters. I saw the first designs of these characters and really didn't get it at first, but they look far better in animation.To me this was a temped to make the show for a more kids audience but still a neat way of doing it. I at first didn't really like what the characters looked liked at first but I it has grown one me.
There are like 3 legitimate parody Scooby-Doo shows (4 if you count What's New Scooby-Doo to an extent, I sort of don't and sort of do). This one, Pup Named, and Mystery Inc (being a darker parody, but with some lighter gags here and there). This one seems to be partially tongue in cheek at least. I'm glad that Daphne's Pinkie Pie-ish behavior has cooled off since the first few episodes. I get that they wanted to give the character an interesting angle and they didn't want her to be the her the girly girl fashion plate character (who she was only during Pup Named Scooby-Doo, but even then it was parody) she became since the movies. Movies also being parody. Other than the design and more early Family Guy-ish, Phineas and Ferb type humor, it's pretty much the same Scooby-Doo. Kinda makes me worried because law of averages says the next Scooby-Doo series (which I hope we don't have to worry about for a while) could very well be the off series where they change the formula.
And yes these are actually more important to the franchise than they seem. After all, breaking up the monotony of the Scooby-Doo formula...makes us desire the formula all the more.