I didn't mean it was counterproductive because of the level design changing, but because using the Boost formula as a base would just make it
unnecessarily difficult for no good reason, when it's easier to come up with a new moveset from scratch, instead of trying to combine two very contrasting gameplay styles. Of course the level design needs to change to accommodate for the changes in the moveset, that's just proper game design. And also yes, bold risks is what I would like them to do, but I believe it is better to start from the beginning, than just adding or tweaking little things of existing gameplay.
I don't see how the Boost and Adventure formula's are at all contrasting. The things replaced by the Boost formula are functionally very similar to what they are replacing in the Adventure formula, and could just as easily be replaced back without too much issue. These are:
Spindash - Boost
Bounce - Stomp
Somersault - Slide
There are also several additions to the Boost formula, none of which I see having any sort of meaningful contrast to the Adventure formula. These are:
- Drift
- Quick step
- Wall jump
I can't think of any way in which any of these additions would actively hurt the Adventure style of gameplay if they were added onto it. Especially in regards to the often contextual nature to them, only allowing the player to make use of them in certain sections of the stage that allow them in several of the games that feature them. Overall, I'd actually say that the Boost and Adventure styles of gameplay are largely very complimentary, perhaps even by design, with the only major difference being one of level design, so let's discuss that momentarily.
Adventure stages try to feel like big open environments, though they still often amount to a mostly linear experience. They are somewhat designed like a 3D equivalent of Classic formula stages, with the player being able to choose whether they would rather speed through the levels or slow down and hunt for hidden goodies, though the concept of "Upper" and "Lower" paths is largely absent compared to the 2D Classic stages. Alternative pathways do sometimes exist, but are generally rather brief and mostly just exist to reward the player with shields or 1-ups for thinking outside the box to find them, or to be used in later bonus missions in which getting to the goal is not the main objective.
Boost stages try to feel like big open environments, though they still often amount to a mostly linear experience. They are designed like big hallways filled with obstacles that the player is generally expected to barrel through at breakneck speeds with little room for slowing down. Sometimes hidden goodies are hidden just out of sight for you to collect if you do decide to take things slow, but there's never much in the way of alternative pathways that last longer than a few seconds aside from very rare exceptions. Said side paths usually either have nothing in them, or might reward the player with something like a Red Star Ring.
In summary, the key concept behind both Adventure and Boost stages is largely the same, with the only major difference being Boost's general expectation of the player maintaining higher levels of speed while Adventure stages encourage you to slow down a bit. Imagine for a moment being placed in a Boost stage, but with the SA2 toolkit instead. Spamdash could be used to barrel through the long boost corridors, grind rails would function pretty much normally, somersault could be used to get under slide passages, bounce could be used in stomp sections, drift and quick step sections could be easily traversed by just running normally with the occasional homing attack mixed in to deal with enemies, and wall jump sections could be passed with bounce, homing attack, avoided entirely, or sometimes count as dead ends. As such, for the most part SA2 Sonic would function perfectly fine in a Boost stage, aside from being a bit slower and rarely getting blocked off by a wall jump section too high to cross. The occasional water running section might also function as a roadblock depending on if Adventure Sonic is allowed to run on water at top speed and if there's any shortcuts that could allow such sections to be skipped entirely.
Now let's consider the complimentary scenario: Boost Sonic placed in an Adventure Stage. At first you might expect him to just barrel through the stage with ease, but the Drift, Quick Step, and Wall jump will almost never get used, Stomp and Slide hold no real advantage over what they replace, and Boost could just as easily get Sonic killed from moving too fast into obstacles as it could help him navigate through long stretches quickly. Overall, he would end up not having many major hurdles to deal with, but end up generally just feeling the same as if he were Adventure Sonic but with a slightly different toolkit and worse handling and some faster clear times when the stage design allows it.
In either scenario, the level design is actually surprisingly functional with either toolkit with only the occasional exception. This largely isn't too surprising, as Boost feels like it was made to be an evolution of the Adventure formula rather than an outright new experience. The level design focus has shifted to constant speed, but Sonic's playstyle itself isn't really so different. Indeed, it's the Adventure Era stages that translated most faithfully into Generations Console/PC in comparison to the Classic Era stages, with the biggest difference being the 2D sections.
With all of that in mind, I don't see the incompatibility you are talking about.
In regards to starting fresh, the whole thing loops back to what I had said in my first post: It's largely a matter of identity. The designers would need to come up with a playstyle that that is nearly entirely new, but that still feels familiar in that it feels like you are playing as Sonic, and not some other character wearing a Sonic outfit. The question then becomes this: What about Sonic's moveset is most iconic in association with him as a character and style of gameplay, and how do you reimagine these things into something that is recognizable yet feels fresh, and also has a good flow together so as to have a satisfying gameplay? From here, a list of things to consider reimagining into a new form could start forming, such as for example:
- Spindash
- Homing Attack
- Drift
- Boost
- Lightspeed Dash
- Tails Assist
Once you have such a list formed, you could start moving onto thinking about what style of level design you want to be building, and how Sonic's toolkit is going to be interacting with it. This is where you are going to want to start thinking of entirely new uses for these abilities that haven't been done before, such as how in Unleashed they expanded the number of things you could homing attack into and in Lost World they merged the Spindash with the Boost. You may end up deciding that some points on your list don't fit well with the style of gameplay you are going for and ultimately nix them, such as not being able to find a use for the Lightspeed Dash in an open world environment, or the Homing Attack feeling too strong for a new 2D experience you are building, or you simply just not having any ideas on how to reinvent say, the Drift.
Overall though, the goal is this: The moveset needs to feel new, yet familiar. Simple and easy to control, but with a high skill ceiling for experienced players to pull of complex movements. A good sense of flow so that the playstyle doesn't feel clunky, but not going too far with it to the point that it feels slippery and/or unruly. Sonic should be capable of moving at high speeds, but also capable of slowing down when the player feels a need for it. Most importantly, the level design should compliment all of this so that Sonic feels suited to these environments, but with some room for challenge.
It's always a much bigger challenge to entirely reinvent a playstyle than it is to simply refine it. This is probably my biggest curiosity right now in regards to Frontiers; are they reinventing Sonic's moveset entirely like this, or applying his existing moveset into a new context with some new additions here and there?