The biggest fault with G+ that we see (besides the obvious fact we'd prefer to not pay extra for it) is that the top 8 attractions among the theme parks are excluded (and I know there are times they knock that down to 4 exclusions). It's a change that makes G+ way less effective than FP+ or MaxPass from the recent past. FP, FP+, and MaxPass all had their pros and cons, as does G+. We thought G+ would be more like MaxPass, which we found to be the best of the 'fast pass' type options. But removing so many attractions dilutes the value in so many ways.
I guess if there was a perfect solution that everyone liked, they'd have it by now. But that doesn't exist.