The only thing about Rock Band 2 that feels 'off' are the damn HOPO chords. They make no logical sense. All they do is trick you into missing a note that you would've otherwise happily strummed. The adding notes to sustains in World Tour was a better idea. I like the open strum addition to the bass in theory, but I haven't played enough WT to truly develop a feel for it. There are lots of places where an open note would help lead guitar too. The Thunderstruck intro especially.
Unfortunately World Tour did little else right. The whole engine feels bad in general, the songs weren't great. I'm curious about GH: Metallica, Smash Hits, and GH5 but I'll probably wait until there are some cheap deals on them.
I'm largely committed to the Rock Band platform. I love the fact that I have 50+ songs from the original, 80+ songs from RB2, and just shy of 300 downloaded tracks all easily accessible from the same playlist without swapping discs. I have lots of GH3 DLC, and I had a lot more fun with that one than World Tour, but frankly I've just started buying old GH3 songs in Rock Band 2 so I don't have to swap out discs, especially with the Pepsi free DLC promotion. (free in that I was going to buy plenty of soda anyway, that is)
Oh, also, it's actually possible to calibrate RB2 decently for HDTV lag. Especially if you have the autocalibrate guitar controller. GH:WT has been completely impossible to get a satisfactory calibration for me.