-Better use of lower playfield, especially during mtiball. Really wish it was in okay during multiballs and had any use outside of three Hell song modes
-Make it so the cannon drop target isn't always the middle one (current exceptions: multiball begin jackpit and FTATR mode is only time you shoot at other targets. Would like even more if cannon required you at times to hit other playfield targets (as it currently does for Super Jackpit w bell). Would be nice if asked you to hit left loop or ramp at certain times
-Some sort of Wizard mode other than Encore, which is super hard and removed from any high-score or normal play strategy
-I don't mind the imbalance Hell's Bells creates, though others might
-Make it clear that Rock n Roll Train requires a combo shot, not just left ramp. You sort of have to just know this at moment.
-Create some incentive to actually play the "bad" songs (Let There Be Rock)
-should be way to crank or turn down volume via flippers or buttons without opening coin door if game on free play (so doesn't affect location games)
-the scoop behind the bell is terribly underused. So many cool things could be done w this relatively rare shot. Right now just acts as gateway to Hell in only one mode (Hell's Bells)
-The Song Bonus situation is a but messy and incredibly confusing to newbies.

Any others?

Also on phone so apologies for many typos above