I never had much interest in the Guitar Hero franchise, because meh.... playing a fake plastic guitar with buttons similar to the old "Simon" game I had as a pre-teen seems rather pointless. People put all that effort into mastering it and it's a useless skill for anything else. Why bother?
Rocksmith did interest me, because it was all about actually learning songs using your favorite electric guitar. But only a few minutes into that one, I realized I wasn't getting into it either. I like what they tried to do with it, but like others here said -- why no standard guitar tablature? The whole scrolling neck thing works for Guitar Hero, but I found it pretty disorienting and non-intuitive for learning music on a real guitar. Maybe offer a toggle between views/modes at least?
Also, maybe it's just me ... but I feel like the era of the "guitar god" and stadium rock is pretty much behind us. These games still cling to that theme, that you're trying to play bigger and bigger live shows, seeking the applause of the fans, etc. etc. But do people even really relate to that anymore? I guess it's one mechanism to try to make the game rewarding -- but part of me feels too old for that nonsense. I want a game that makes practicing songs and new guitar techniques fun, but without making me pretend I'm 25 years younger and striving to make it big in the era of 80's hair metal.