So, I started up with the goal of going high-intelligence, and focusing both my skill and attribute points towards having minions.
Turns out, that while my Incarnate and Totem scale with my summoning investment, they don't receive any bonus from intelligence. And, in fact, it really seems like they're underpowered.
Maybe that's due to the fact that I could have a dwarf character with only vitality and summoning, and his summons would be JUST as good as the Lizard Wizard who actually focuses on the arcane.
I think a summoner being a specialized thing is fine, and thus you don't want investments in it to benefit other things, but it genuinely just feels like it was supposed to benefit from intelligence, and just doesn't.