One of my worst experiences with wrestling games was with the Smackdown series and it's lack of selling a move. I remember countless times hitting a guy with a chair, dragging him near the top rope, going for my finishing move, then having him counter. Or even worse, since nearly all top rope moves ended with a pin, any top rope move in a Ladder, escape cage, Table, TLC for title, etc would result in the opponent immediately becoming conscious. Does PWX solve these issues?
I think that there should be some type of formula for all the moves, and have all the moves ranked in a tiered list, to calculate selling time. If you are hit by a level 1 move at any part in the match, the sell time should be relatively low, whereas a level 2 move in the beginning should have a low sell time, but a higher sell time later, so on and so forth. The top rope moves should allow for a combination to decide while doing the move if it will end in a pin or not.
I really like your idea of selling times changing throughout a match. I think this would help the flow of a match tremendously, and realism because you see that often. I really hope the PWX team considers this; it shouldn't be too hard to implement, just change how long the repeating "sell" animation on the ground goes for.
If anything, I expect to not see it in Uprising, but I would like to know if this is remotely reasonable. This would put the game over the top. SVR sucked at selling miserably. No Mercy's selling was pretty find because it calculated fatigue (which is basically the same method where health equates to your overall recovery time).
Legends of Wrestling had a pin-button window (really short, especially on "Moonsault" and "Turnaround Moonsault") for most of the top rope moves, and the AKI games would have you pin a splash move if your opponent was perpendicular enough (besides, there was rarely a match in NM that didn't have "pin" as a win condition).