Trevor really isn't a go-to type of guy at the end of a game. You need players like the Hollins boys to have the ball in their hands during crunch time because they can create their own shot (especially Dre) and hit from anywhere on the floor. Trevor's offense is limited to second-chance slams, tip-ins and mechanical moves on the block. LOVE that he's back again but I don't think he is going to be an offensive force. TM makes is $$$ on the boards. So, to answer your question, the Hollins boys and Rodney Williams will be the go-to players. Welch missed too many FT in critical moments last season for me to trust him. He's a decent backup PG in the B1G.
I can understand how the ability that most good guards possess to hit shots from anywhere on the floor would give them an advantage over a true post guy like Mbakwe, but unless you really need a three, I don't see how Austin or Dre hitting a jump shot is better than Trevor powering it in. In fact, if you only need two points, Mbakwe might actually be a better option than having a guard go in and get it. I would say that Trevor is a go-to guy, and his excellent rebounding ability is very helpful for cleaning up when the guards miss. As far as straight up getting points, you are probably right that Mbakwe can't score in as many ways as Dre can, but he is quite the presence inside, which could draw some attention away from our deep threats (Dre, Austin, Julian etc.), cause the defense to collapse then kick out for a 3, so he still helps the guards just by being on the court. Even if you do need 3 points, Trevor has a knack for getting fouled, and in his limited playing time last year his free throw shooting was up a whole 10% from 2010-11. Getting the hoop and the harm isn't the most reliable way to score three points, however, and if you need three in a clutch situation, just shooting a three is a better decision than doing what Austin Hollins did at the end of the Illinois game at the Barn (though he made it work, and we won the game, so it's hard to be too mad at him
).
Julian Welch is fine other than his (lack of) clutch free throw shooting ability, but it sort of depends on what sort of clutch situation you're in. If you're just holding a small lead at the end of the game and the other team is fouling, then Joe Coleman is probably a better player to have in the game because he has shown an ability to hit those free throws when needed. If you absolutely must hit a three at the end of the game to stay in it, and you don't have Evan Smotrycz on your team (grr...), then Welch is a better player to have in because he is the best three point shooter on the team as of now, though I wouldn't be surprised to see Dre surpass him, but I don't think many would dispute that Dre belongs on the floor at the end of the game. And who knows, maybe the whole missing late game free throws is just a mental block in Julian Welch's mind and something that he will get over this season, I certainly hope so, I really like Welch.