I was very skeptical of Rocksmith then i first got it, but I've come to love the way it makes lots of things fun: particularly learning songs i never would have before buying it. I like to try to incorporate my own style into a lot of the songs, and Rocksmiht allows me to do that by not penalizing me for playing around in between the notated song parts. However, as someone who prides themselves on their soloing technique, I've found one vital issue with the game's interface. My style leans heavily on my various styles of vibrato: it's the lifeblood of my music. While playing Rocksmith, I've noticed that the sustained notes WILL NOT SUSTAIN if you apply vibrato to the string of your guitar. You're denied the points (when in all honesty, you should get a significant point BONUS for vibrato). This is a huge issue for the game, especially given that many people are using this game to learn the instrument for the first time. That is encouraging a very bad habit, or rather discouraging a very good, and essentially musical one. I don't want to see a bunch of people in a couple of years sounding like robots, keyboards, or dead cats in my favorite guitar stores! Please Rockmsith developers, do something about this issue!!!
I noticed this effect as well. If you use a very strong vibrato, the game scores the note off- tune. I have found that if I just use a mild vibrato, my playing sounds nice and also scores correctly.
I understand your concern though. I'm a lapsed guitarist returning to the game, and my vibrato isn't that strong yet anyway (need to build up strength, etc.). But even at my weak technique level, I can still effect my score by overdoing it.