I don't disagree that the Sulu/Excelsior idea had a lot of potential. And for those who had a problem with Takei's acting (I'm not one of them), he would've had a whole ensemble cast to play off of, and getting the show he desired might have brought something out of him that people hadn't seen thus far.
As for Cho doing a Sulu show, I think he probably would. He's done TV before (Flash Forward), there's less of a stigma for movie actors to do TV shows these days, and let's be honest, it's tough for any actors, but especially actors of color to get lead roles in films or TV shows. If offered, I think Cho would probably take it.