Never saw scrappy doo so I cant comment on how good/bad it was. Scobby doo was annoying enough for me and any recreation or addition to that show, setting, or whatever you want to call it is a definate one to avoid IMO.
What I find interesting is the hate of Looney toons. I think the hate is because the cartoons were mostly made for generations that are dying out. For the time the cultural relavence and "stereotypes" that the cartoons portray are spot on but now our culture has and is changing even more to the point where the characters just dont fit in the culture. It would be like us speeding ahead to 2110 and expecting people to like Dragonball Z, Thundercats, or Courage the Cowardly dog as much as we did. Or how the Bond girls in the James bond movies were once central characters that portrayed the ideal of feminism in the 1950s-1970 but today theyre seen as little more then women cast in B rated action movies.