I don't think anybody is or should be worried that Green is going to be a break-out star this year, just that he may actually produce on the court. People keep bringing up how he was inconsistent with us, but aren't factoring in that he was our go-to scorer for a period of time. He will never be asked to be that with Cavs, but if he surprises and is a difference maker with the 2nd unit, then they got very good value.
Basically what I think the OP is saying is that, contrary to popular belief, Green might not suck and that isn't a good thing for us. Also, with so many young players already on the roster, Jeff (or even Gerald) Green might have have been a better option.