I see some consistency in what your saying, yet I don’t like the idea to have to switch to a secondary screen for such a core feature.
It surely won’t. As discussed extensively here, if a button requires an on-press event, there is no way to have any secondary event attached to it (be it on-release or on-double-tap…).
I don’t really know why you are mentioning part erase, yet what you are saying is probably feasible although I don’t really like the idea of 4 actions bound to the same button. Starts being a bit messy.
I don’t think you understood what I meant by “transitional states”, so let me explain a bit further. Let’s take the example of “next part”. When you click on “next part”, and the next part actually already exists the button becomes then labelled “cancel next part” until the end of the current track to give you the opportunity to cancel the action before it happens. Same behavior exists for “cancel rec”… This is what I call transitional state. This is not managed at all in your flow.
Apart from that, another point that I noticed in your proposal is the fact that the “next part” button is attached to the on-release event which is contradictory with what we want (and actually already in test AFAU as per what @BrennanSingularSound said here).
In conclusion, even if liked the initial idea, the more I dig , the more I see problems that can’t really be addressed by this solution. But as I said earlier, this is not because the complete idea is not really feasible, that we have to get rid of everything, and there are clearly things like the EOL management that deserves having a much deeper look at…