Maybe to add a new dimension to your improvisational solos you could learn a few more scales. Hopefully you are familiar with the "blues scale". It is very important for soloing, not just while playing the blues! Perhaps you could learn the harmonic minor scale. But if you are more into the "classic rock" sound, it won't seem to useful to you. You could also use modes in your solos, they can sound really cool. No matter what scales you utilize, THE MOST IMPORTANT thing is to know them so well that you don't have to think about the notes you are playing. If you can acheive this, you can put alot of "feel" into your improv.