Starkrun: The original series was amazing, and when they tossed robin (as a man) in it still worked. then they made robin the boy and the the show tanked.
Batman beyond is also extremely good. It takes up where Batman the animated series lets off and has Bruce in the future battling a few of his old nemeses. But its just done so well...
Well, part of the problem with the "second" Robin was that they tried to do a little too much with the character.
See, the original Robin, was... just that. The original Robin. Dick Grayson was true to form. The second Robin, while they called him Tim Drake, was in reality a weird, jumbled mishmash of the comics second and third Robins. He shared the third (and current) Robin's name, but his personality and background were more the second Robin's, i.e. Jason Todd's.
And seeing as how Jason was literally killed off by fan decree... (DC actually set up a hotline where people could call in and vote whether or not they wanted Jason to bite the dust, and apparently, people voted to off the kid.) You can probably imagine why he didn't turn out to be as great a character in the show, either.
I wouldn't say it "tanked," necessarily, but I wasn't too big a fan of DCAU's Tim. But Dick -was- getting a little too old for the role, and I suppose they did want to do things with the Nightwing character... which was a good choice, if you ask me.