I mean, not to bust your balls or anything but you're rocking a Witcher avatar and you posted that Wild Hunt in your GOTY. So, Divinity isn't your first cRPG.
Ignoring that, it's all pretty subjective, I agree, but the pyramids, the portals, the micromanaging each party member, the combat encounters that demand paying attention to elements, landscape, etc all make Divinity a far, far, far, stupidly far, more complex game than the straight forward Pillars. I don't see any angle where, taken in a vacuum like OP, Pillars isn't the infinitely more accessible title. And it's great, to boot.