He was excited for the change. Basically saying he was eyeing BYU harder because Bronco was leaving. It didn't mean right then that he was all in on BYU, just that the combination of Bronco leaving and seeing who the new guy would be actually raised his interest level in BYU.
Chazen is right that there wasn't much "reading into it." It's pretty much what he said. Now, reading a little much into things like Bronco alienating people with his aloofness, yes. That's definitely reading into it probably too much because it's putting words in Tanielu's mouth that he didn't say.
But what is clear is that he became more interested in BYU with the Bronco news, for whatever personal reason that might be.