D&D General Ability Score Potpourri (Split Dex? Whither Willpower?)

[CubicsRube]

My never-gonna-happen preference for 5e would be

Might - Strength + Constitution combined
Agility - AC, dodging, acrobatics and the like
Dexterity - to hit with ranged and finesse weapons, sleight of hand, all other handy stuff
Wits - Intellect, convincing, perception, insight
Will - Persuasion, intimidation willpower and the like

This creates a better balance of stats that I like and allows some archetypes I'd like to try out, like the witty and perception sherlock holmes character or the high might high will stubborn and intimidating warrior. (Yes I know these can be done otherwise, but it's simpler with this split)

 

[Cadence]

The psionic post has me wondering about what traits make someone ready to have arcane/divine/primal/psionic/ki/rage powers. Is that something any person can do with enough intelligence/wisdom/whatever? Or is there something beyond like in a lot of fantasy series where one needs predisposition and hard work.

Does every character having a single affinity slot (chosen at creation as arcane/divine/primal/psionic/etc) make any sense? (Does it becoming a dump stat for all non-casters mean it needs to be totally different?).