How can we get more in depth character customization?

[Reynhart]

Unfortunately, "Illusion of Choice" will strike and make the entire thing completely worthless when theorycrafters math out the best one.

No, the problem is within the game itself that any content can be beaten the most efficiently by the same "best" setup...or, worse, than even if different content required different setup, the game probably would allow you to change it instantly at no cost at all so that you wouldn't even have to weigh your choices.

I remember putting points into dexterity as PLD because I thought it'd make my shield block more often.

It used too, in ARR, but since SE don't want things to be too hard, the drawback of blocking less was non existant, so...MOAR DEEPS !