The set of performance pads modes is defined by design on each DJ hardware.
But each DJ have their own control preferences and mixing habits.

Sometimes, to choose a new dj hardware needs concessions.

For example, Slicer mode is important for you and Pioneer DDJ FLX10 seems to be the best hardware for you, but unfortunately Slicer mode is not set on DDJ FLX10 !

Excepting Stems mode for a list of primary/secondary hardwares, we aren't free to build our own set of pads modes.

It could be interesting to open Performance pads to personalization.

Full opening would be great, but it's understandable that each hardware company wants to design their products to make the difference with the competitors.

A possible way to implement pads modes personalization could be to let the first layer (one clic) and the second layer (double clic) defined by design and open a (full or partial) third layer (Shift clic) to personalization.