Can someone with an insane amount of time on his or her hands please do the following: Find the average shooting percentage for UConn for each of the past 10 seasons at each venue. Find the average shooting percentage for opponents for each of those seasons, at each venue. Subtract opponents' shooting percentage from UConn's for each venue in each season. We would then have a better, though still not perfect, measuring stick to find out if UConn really shoots better at Gampel compared to XL.
I doubt anyone will have the time or will to do this, which is understandable, but short of this type of analysis, I haven't seen any actual evidence to support the claim that UConn shoots more poorly in Hartford compared to Storrs. To be clear, my "feeling" is that the team does perform better in Gampel for sure, but I like data and hate feelings.
All that said, for a hundred other reasons, I don't think UConn should play games at the XL Center, with the possible exception of one marquee matchup per season, when students are on break.