You can basically sum it all up by saying that Harmonix employs actual musicians who are also very talented. Hence Rock Band being more musically accurate.
On the other hand, Neversoft are a games company who know a thing or two about making a good game. Which possibly explains why Harmonix rigidly stick to their principle of making you play songs over and over and over and over again during the tour mode - yes, we know real bands don't just play songs once and never again but it gets boring quickly.
This is one thing I will always stick to - all songs should be unlocked and accessible at any difficulty for Quickplay with no save disabling cheat codes from the moment you first start the game.
And I can dig what you're saying and I agree, Neversoft have a lot more experience making games, considering they make what as many versions of a franchise as possible until they're killed it? (see Tony Hawk)
But on a serious note, yes, they know more about gameplay, but, with a music game, the heart of your gameplay is the music and when the music is better, as is with RB, you have a superior game. Unless the other parts of the game are awful, which I don't think anyone could say that about RB.
What you've said about having to play the same stuff over and over again, I agree with you to a point, it does get tedious at times, but other times I enjoy it.
The best part in regard to the setlists is the integration of the DLC