(or, "You Can't Be A Serious Superhero In Short Shorts")
Everyone knows who Robin is. If you think about the best-known superheroes in popular culture (indeed, arguably the best-known figures in popular culture, period) Batman has to pop up right near the top of the list...and everyone who knows about Batman knows that it's not just "Batman", it's "Batman and Robin". The Boy Wonder is an essential element of Batman's storytelling engine, and has been for generations. He's a handy audience identification figure for younger readers who want to imagine themselves adventuring side by side with their hero, he's a handy means of providing exposition (so that Batman doesn't have to talk to himself quite so much), and as a crimefighter slightly less competent than the Darknight Detective, he's a useful source of plot complications if the writer needs to extend the story. (And he's also a source of comic relief, if your source of humor trends towards terrible puns and the overuse of the phrase, "Holy (fill in the blank), Batman!")
But all that is Robin's role in Batman's storytelling engine. What happens if you want to try to take Robin and turn him into a lead role? How do you handle taking the sidekick and making him into a hero? That's a bit of a tricky question, one that DC struggled with for many years while trying to establish a storytelling engine for Robin. As we can see from 'Showcase Presents Robin, the Boy Wonder', they weren't quite sure where to begin.
They began by establishing him as more of a grown-up, which is a good start. Robin kicks off his solo career by leaving Gotham behind and going to college. (This is a bit of a backwards step, as most of the people writing Robin at this point had left their teen years behind a while back--there's very little as painfully awkward as reading dated teenage culture references. It's like listening to your dad try to be "hip".) With his own stomping grounds and a bit of distance from Batman, Robin has to be the lead hero because there's nobody to save his bacon (apart from occasional guest shots by other "young heroes" like Batgirl, of course. And a guest shot or two from Superman. And okay, yes, Batman does drop by campus a few times to see how he's doing. But, um...yeah. Sorry.)
Other arguable mistakes would include keeping the iconic Robin costume, which is by now practically a symbol of childhood (in particular, the little short shorts and the bare legs (which must be shaved, if Dick Grayson is a college student and still able to keep them that smooth. That doesn't speak tremendously of your macho heroism, being the only superhero on the block who makes sure to use 'Nair'.) The change from 'Boy Wonder' to 'Teen Wonder' seems like a good idea, highlighting his growth, but "teen" tends to connote junior high and high school kids rather than college students, thus having the effect of making Robin still seem a bit young.
But the great mistake is the lack of a rogue's gallery. Batman is out there fighting the Joker, Two-Face, Killer Croc, and Ra's Al Ghul, and Robin's helping out neighborhood kids and trying to figure out who's sending threatening letters to the Dean. One of these two is going to be seen as a major superhero, the other is going to be seen as a sidekick. One guess as to where Robin falls, here.
It really isn't until the 80s (and arguably the 90s) that Robin begins to work as a solo hero. Dick Grayson gets a major makeover from Marv Wolfman and George Perez, turning him into Nightwing and making it clear that he's ditched the trappings of childhood completely, while the new Robin, under the wing of Chuck Dixon, ditches the puns, the short shorts, and many of the much-derided elements of the old Robin, and begins accumulating his own supervillains to fight as well. (Dixon also has a hand in the storytelling engine for Nightwing, his run on that book establishing a home city, a rogue's gallery, and a supporting cast for the former Robin. Of course, all that's gone now, and coincidentally, the book is kind of floundering. Go figure.)
So now, instead of one Robin who doesn't work as a solo hero, we have two that do (three, if anyone here actually cares about the resurrected Jason Todd. Anyone? Anyone? No, didn't really think so.) What made the difference? Arguably, Chuck Dixon. As a writer who's always been concerned with the nuts and bolts of good storytelling, he made sure to surround his characters with the elements that made their storytelling engines work. He made sure the characters had easy access to story ideas, if for no other reason than it made his job easier, and it made those characters work in a way they hadn't before...and in a way they haven't since, as the supporting casts he built up got killed off in the current climate of "shock comics" that exists at both of the Big Two. If there's a lesson to be taken away, let it be that. A hero without a good supporting cast, a good setting, and a good antagonist is really just a sidekick. And not every Robin has a Batman to hang around with.