Colisseum and Spotlight Are Terrible - For Now.

I agree with all of this. Since you can't see how ST Luke works in his intended team or how he works with the rest of your roster, there's no way to get excited about him. And importantly for CG, no way to get a sense of whether you want to spend money on him. 

It's not even very clear what spending money would actually do for you or what difference it would make. He'd still just sit there in his own separate game, doing nothing for the rest of the game.