The new abilities won't stack. The whole point of the new system is that there aren't a ton of abilities you can turn all to "on". New abilities would be more options you can replace the thok and spindash with. For instance, one of the ideas put forth while we were setting up the system would be the ability to replace the spindash with a Super Peel-Out style dash move.
The idea is that you give up an ability for something else, instead of adding a ton of abilities together to make a character.