Like others have said, this is a good problem to have. That last bit of the season really cooled a lot of people on Ralph, but he can play. If he improves from his second to third year like he did from his first to second year, he will be a force. Ralph showed his huge upside at times last year (St. Joe's, at Indiana, Purdue, and a few others). He could be the best passing center in the league (only Mirkovic had more assists per game last year for centers), and he's getting better defensively and on the boards. Right now, for Ralph, it's all about developing consistency. In his junior year, it will no longer be good enough to bring it every few games; he needs to bring it every night. Before he's gone, I think Ralph will be a 1st-team All Big Ten player. I really do.
As for Colton, like Ralph, he needs to become more consistent. He outplayed Ralph down the stretch, but I think RSIII is the better player. But when they're on the floor together, they're tough to stop. Could be even better next year if we put another big (like Mbakwe, hopefully) at the 3.