I think this could balance it too. It also makes it so you can't really take knuckles' wall climbing paths with it, since those usually require climbing to the side.
Yeah. Only GFZ, THZ, DSZ1 & ACZ2 can be done. Though, you can take tons of Amy, Fang, and Knuckles routes since all usually combine.
GFZ2: Ah yes, the act that introduced split paths. It can. Just not Amy's secret garden area.
THZ1 Knux: Can be done. All routes. The 1st spilt looks as if it can't, but it really can. Sure, you can't break the wall that splits up the areas... But with mods or Noclip you still can beat it. Just run up the side, and jump.
THZ2 Knux: Same as THZ1. I beat the area as Fang with Hookring, and Sonic + Tails. You just gotta run up the wall and stay near the side. The rest is doable. Then, just Noclip through the walls.
DSZ1 Knux, Amy: Only Knux this time. It's just a wall.
ACZ2: Yes. Yes it can. You can beat Knux and Fang's routes... But Amy is impossible.
The rest and unmentioned can't be cleared.