Crimson Longinus
Legend
In my opinion, there are basically two options: either every class should be viable in every pillar, but contribute to it in different ways, or every class should specialize in a pillar and be weaker in others. The direction 5e seems to want to go in is the latter, and that’s a valid choice, but in that case non-casters should have more tools to contribute outside of combat in different ways than the casters do.
I don't think it is a problem is some characters are weaker in some pillars and stronger in others, as long as they're not completely useless on any of them. Everyone don't need to contribute exactly equally for every pillar, but everyone needs to be able to contribute something to all of them; doing nothing is boring and this is a team game. And this doesn't need to go by the class. You should be able to build a wizard who focuses mostly on blasty spells and has less utility, or skill monkey rogue with a lot of connections that, whilst not being useless in combat, is not a super assassin etc. One subclass that exemplifies to me what not to do is the berserker barbarian. It has no out of combat utility beyond skills, and in combat they use frenzy to make them super killy in exchange of exhaustion, which gives them disadvantage on all ability checks rendering them pretty much completely useless outside the combat. Terrible design.