He has some potential to be an interesting ally, but... wouldn't it be like 30x more work to make him an ally with usable limits, weapons etc.? And how would he fit into the story? Unless it is possible to just swap his model and call it a day (I don't think it is).
So, new allies are always fun. Making him a recurring boss would be cool though. If it is reasonably feasible, then make him an ally. If not, then make him a boss and use the leftover motivation and effort on a more meaningful project. Whatever you decide, Good Luck!