I already said he would be a step up("upgrade"😉 for the Cavs at that position, but he's not going to elevate them to the next level. Isn't that what Cleveland is looking for, a Point Guard that will help elevate there chances to a championship.
Melo got to play alot more off the ball when Boykins was on the court, than Miller. When Miller wasn't hitting his shots, and the offense wasn't opened up, Melo had to create his own shot, just like Lebron would have to do when Miller becomes incosistent. When Miller is consistent, yea Lebron will be able to play off the ball more, but that's not going to bring a championship to to the Cavs, or even get them in the Finals. If they get Miller, they still won't be able to beat Detroit, or Miami with a healthy Shaq.