To summarise my thoughts on 2.3: I worry that 2.3 will end up overdesigned.
Firstly, Sonic's ability: Sonic's new ability looks like something of a swiss-army knife, being a wallclimb, dropdash, and water-skip all in one. Putting aside that water skipping is already an ability inherent to anyone who can spin, and the dropdash just doesn't work as well in SRB2 as it does in Mania due to the relative scarcity of slopes in SRB2's level design, this new ability completely loses the beautiful simplicity that the thok has. Despite little depth being intentionally put into its design, it provides a wide range of creative and skillful movement options, such as momentum redirection and assistance when badnik bouncing, thanks to its simple design. Providing a range of abilities may actually reduce the player's freedom with the move, despite what one would assume, as since more mobility options are being provided the player is essentially being told to pick one out of what they're given rather than invent their own.
Secondly, the physics: I personally really love that SRB2 hasn't submitted to the Mania hype and gone with Utopia-esque wallrunning and the such. It gives the game a strong character that sets it apart from the rest, and I'm confident that this uniqueness has had a big hand in the game's rising popularity. Adding stronger momentum physics and wallrunning would completely destroy that, making it just another generic 3D Classic sonic fangame. Sure, it'll still have the novelty of being made in Doom, but that's what'll make players play it once, not what'll make them keep on playing. The accel-mom branch does nothing to quell my worries. It's just... not fun to play with. It feels like I'm dragging a hedgehog-shaped stone around by a rope. If it were up to me, all I would do is fix the momentum cut while not spinning, maybe make water-running a global ability and leave it at that.
Many users in the community have echoed these opinions, even in this thread. I hope STJr take note of this and at least do something to show that they know what they're doing and aren't just running wild with creative freedom now that the old guard are gone.