I don't really think aiming Sonic's thok up/down would be that complicated to understand, it would just be really ugly in Software mode. It's incredibly obvious and intuitive that aiming up thoks up and aiming down thoks down, and that because of gravity aiming up is harder than aiming down.
I don't think you understand the issue here. Proposing that an ability is controlled via adjustment of the vertical camera position is a concept that completely neglects the impact it will have on keyboard users and some gamepad users who are negatively implicated by it being required.
Mouse users can afford to aim the thok up and down, because all it requires is a flick of the wrist. But this would unnecessarily force gamepad users to modify their control schemes to allow for manual camera panning. I can give you a first hand example of this, as my gamepad control scheme entirely depends on the lock-on button as one of the shoulder buttons for camera movement, with actions on the four face buttons for a conventional platformer control scheme. There's no way I could ensure that it's possible to perform these actions while also touching the right stick, and so this feature would unnecessarily force me to reconsider my layout just in order to use all of Sonic's intended features at a base level.
This isn't even the biggest problem though, as any keyboard user who lacks a mouse must use the arrow keys to turn instead, and in doing so they'd be continuously repositioning the camera into/out of awkward positions by constantly transitioning between two arrow keys which slowly move the camera up and down; the fact that the vertical panning is visually smoothed also leaves the player with very little visual feedback on how long they'd need to hold the key down for to get the camera in the position they want, or (god forbid) back into neutral so that Sonic fires straight forward again.
The entire point of integrating ficklecam into the last update was to reduce the player's control load, and what you seem to be asking for would completely work against. It'd be bad enough for gamepad, but for keyboard-only it would be a complete disaster.
However, if aiming via camera is too big of an ask, the only alternative to achieve the same result I can think of would be to make it so Sonic can cycle between three modes. Forward thok, Downward thok, and Upward thok. This could be cycled either via mouse wheel, 1 2 and 3 buttons, or by pressing spin midair without a shield. This method would lock Sonic in to three set angles rather than true aiming, but it would make it so that you don't need to use the camera to aim at all.
The mousewheel and 1/2/3 isn't feasible, for some of the reasons stated above regarding control load. The "spin" method could theoretically be fit into the existing control scheme, but it would run into conflict with shield actives, which would make it not entirely ideal.
There would need to be some sort of visual indicator as to which thok is currently enabled however. Overall, avoiding using the camera to aim ends up feeling a lot more complex to me than just aiming with the camera,
For Simple Mode, it could just function the way it already does. Horizontal only, but you can aim in directions other than where the camera is facing.
Aiming in all horizontal directions isn't a
feature, it's compensation for the fact that controller users don't have the most accessible or precise methods for redirecting their camera position. What you're suggesting here benefits mouse users exclusively to the detriment of gamepad and keyboard only users.