So I want to bring up a bit of a different take on this. I think we're too busy focusing on Sonic's ability and not looking into the level design itself.
One major difference between SRB2 and typical Sonic level design. Classic stages more often are linear platforming sections with punishment usually being dropped to a lower, slower route.
Where SRB2 differs is there tends to not be a lower route but instead relies on vertical platforming where the punishment for failing is more often death or worse, setting them back further in the level. I think this is shown the worst in CEZ1, ACZ1, and ACZ2. Now my previous statement isn't just to say they have no lower paths. In fact, the beginning of CEZ1 is actually pretty good on that and also including alternate, lower routes. But when you start looking at these stages, notice just how much of their area is just covered with bottomless pits. These makes every platforming mistake even more punishing.
I want to look at ACZ1 specifically. It has this interesting wrapping design where it feels like you're scaling cliff sides to advance. This however creates the issue that failing in the level slips you back even further than before. Then in the second half of the level when it takes a more linear approach, it's all focused down one path (whichever the current one you're on) and then bottle necks into a pully section that is not just long but also has somewhat odd grabbing physics. ACZ2 only emphasizes this design more than before. The paths just get more linear, bottomless pits cover a good portion of the player area, and the mine cart sections get added in, almost at random. This stage also features springs all over the sides of some objects that send the player off the edge with no chance to even attempt to react to them.
I want to bring this back around to a stage later in the game that I think is better designed for newbies than any of these stages: RVZ.
RVZ has a lot going for it. Difficult upper platforming that when failed punishes players with a slower, lower route, very few bottomless pit dumps, and my favorite thing, failing sends the player into physical lava. It eats the players rings, which is fine. It's a late game stage, but it doesn't instantly kill the player for not being able to perform the task at hand. My friends who have tried SRB2 have had a much easier time with RVZ due to its more forgiving way of doing things. Yes it's definitely harder in general than CEZ and ACZ, but rather than killing the player and being a life dump, it allows players another go, usually with extra rings nearby so the loss of rings through the lava is almost a non factor.
I think SRB2 overall would benefit a lot from minimizing how much bottomless pits are used and adding a few more safety nets, either through lower routes or letting them restart the challenge with a punish of damage and a spring back up.
To be completely honest, I think SRB2 would benefit greatly from the removal of lives all together, but I think that's a different argument than discussing Sonic himself.