It's funny how history repeats itself. I remember back when I used to post on these forums right after SCII was released. Everyone used to laugh at me when I said that Sophitia was better than Cassandra. You know what happened? As play styles evolved and new meta-games developed, other people began preferring Sophie, too. Now, when I come to the forums, everyone keeps on saying how she's always been broken. I can assure you, according to the players, this has not always been the case.
Do I think Rock is secretly a top-tier character whose true potential has yet to be realized? No, probably not. But it is far, far too early to write him off as a joke character yet. The fact that, as far as I know, none of Rock's moves were changed with the 1.03 patch suggests that the developers still think he's competitive. Maybe there is some meta-game for Rock that no one's found yet that will completely change how he is played. It just takes one tournament to completely change people's opinions of a character.
Sometimes, it is the player's fault when a character sucks. My Hilde was terrible before I started using charge moves. Does that mean Hilde sucks? Of course not. It means I sucked with Hilde. Give Rock a chance and don't just regurgitate the same tired "Rock is te3h suxorz!1!" crap that's feed to you online, and you might just find a decent character.