You'd have a point if that new guy were say - Whitehead (or like the pg situation with Ennis). But the new guy we are referring to isn't so new, it's Cooney. And his history is much worse than any BT came in with.
So if the new guy you are wishing BT away for is Cooney, then yeah you're nuts.
A lot of people, myself included, hope Cooney gets beat out, mainly because we can't envision enough improvement out of Cooney to be anything but a downgrade from BT. But MG was just shut out by B level Euro townies, so that's not a good sign.
What we know: Brandon Triche was not a good shooter.
Triche was a good defender.
Triche was often careless with the ball.
Triche was a decent penetrator and finisher.
Cooney is a good defender.
Cooney is a decent penetrator.
Cooney has been careful with the ball.
Cooney shot very poorly this season.
Cooney did not finish particularly well this season.
Assumptions: Cooney is a good shooter. He got his game experience in and now he's going to see the ball start to drop. (His mechanics are good.)
Cooney will develop into a decent finisher. He's athletic enough to elevate, he's got wide shoulders, he can get to the rim.
After four years, we knew Triche was not going to become a 45% shooter, a 38% three-point shooter, a careful ball-handler, or a 16-point-per-game scorer. Those were not things he could do at the college level. We don't yet know that Cooney or Gbinije can't do any of those things (though I don't think this year's team is looking for that scoring total from either guard spot). Each is a talented player and gives reason to be excited for this year.
Cooney struggled in a very visible and important aspect of the game this year, but you'd be rash to condemn him based on 400 minutes of basketball (dished out in inconsistent increments, no less). And it's even crazier to draw any conclusions about Gbinije based on some international summertime competition.
[EDIT: also, I'm more confident in Cooney that I am in Ennis - one guy has demonstrated that he can hold his own against Big East players; the other has never had that opportunity. And I still think it's bizarre for a Syracuse fan to want one guy to get "beat out" for a starting job. May the best man win.]