I did consider that a possibility...but I really think that it would be していた in that case.I'm a translator too, and saying that he's a "continuing character" could just refer to the fact that he's been in the first two games. But who knows exactly?
However, given that SSBB isn't technically out yet, maybe that's why...but I doubt it. It wouldnt make sense to say "This character is a continuing fighter for the SSB series" without some kind of "..........except this one."