Doubtful. After all, the preview footage was pretty much ALL malcolms during live gameplay and it looked fine to me.I'm guessing the whole malcom thing is partly because he doesn't have his own team. It would be inconsistent to have a team with just malcolm and no customization in it.
Heck, maybe his model is broken in some obscure manner and needs a complete overhaul to be viable in the game for all we know.
But I also think that it is as you said, it would be awkward to put him in there without a team and that is probably a little much to make the deadline they were aiming for with this pack.
I predict that if the expansion really takes off they'll eventually come out with another addon pack, this time with an extension to the campaign and some new teams (hint to Epic, bring back more of the original UT teams for the uber win) and a focus on the return to the tournament where Reaper can exact his revenge on Malcolm and have to face a necrified version of Jester in the arena.