No doubt G sees big minutes. He's a senior and one of our best scorers. Having him on the perimeter, while helpful during KJ's development, is certainly not ideal. No doubt he will play some minutes up top, but he's not a guard. At 6'7, yes he adds height to the back court. And his defense is not that much worse than KJ's last year -- but KJ was a freshman. I fully expect a sophomore leap from him this year, including his defensive intensity.
Another problem with G up top is that there's a big hole at the 3 when he's playing guard. He can't stay in front of better ACC guards, and having him shore up PG prevents JB from using him where he really hurts other teams -- playing SF where he can hit the long jumper or get inside at will against players his size. When you put him at PG, these attributes are wasted ... because he's not going to drive by too many decent ACC guards, so they play up on him negating his height advantage.
KJ's our best bet at PG if he's making good decisions and being smart on defense, and I think you will see both of those issues improve this year. Certainly, if he's not having a good game or is not handling the pressure of certain game situations well enough, G can be the bandaid. If this happens, it's probably not a good sign for the team.