I totally agree that Blaine will probably get in. If he even goes to college and doesn't move there and just start looking for gigs. But I actually don't think lack of investment will keep him from failure. Look at Kurt, they had no investment for him in this story and he still failed, and nary a second of screen time was devoted to that...
Here's the thing, other than Rachel and Finn, I don't think there's any character the writers have more investment in than Kurt. Yes, he was pretty clearly a prop to Rachel's Broadway dreams this season, and he's constantly treated like crap, but he's without a doubt equal to Finn as the male lead on the show right now. Bad things don't happen to the characters the writers have no investment in. Nothing happens to them and they exist to praise the characters that do matter (like Tina with Rachel).
I also don't think Blaine would ever be "looking for gigs" because I've always seen him as a musical person who can play the piano because it's a useful skill for him to have as a performer. The only other instrument that Darren plays that I could see him playing is the violin (and I guess the harmonica since that happened in EMC).