Yaarel
🇮🇱 🇺🇦 He-Mage
I suggest a combo of both 1) and 2).The truth of the matter is that if you really want to balance the five abilities scores in this heavily combat-based game you have only two options.
1) You force every ability score to matter to both Warrior characters and caster characters.
Or
2) You tie to combat one aspect to each of the six abilities scores that cannot be overwritten by any class ability and has the bulk of its power come from the ability score in which that you cannot bypass prowess in that aspect in any other way.
The abilities correspond to Attack and to Save.
1) All classes depend on all of the abilities that Save.
2) Each class can pick one Attack and dump the other Attacks.
(Of course, some concepts like Ranger will pick two Attacks, one for swords and one for spells.)