What Rock Band does, score you for playing notes and chords a specific way instead of just any way you like, cannot be done except with a method similar to what Harmonix chose with the Squier. Could Rock Band 4 ease up and do something like Rocksmith? Sure, but they can then no longer force you to play the song authentically, ie. the way that the song's artists do. They could display the suggested tablature though, and just score you on the pitches you actually produce from the guitar.