I've been thinking about it, and I've decided that no asterisk is needed. Unlimited dominate may seem problematic on the surface, but the thing can only have one mind slave at a time, so, in practice, you'd basically just be playing a standard humanoid with better mental stats and the ability to switch bodies when one dies. That's nice, but not problematic nice. I'd also say that even with enthrall, it's only +1. The size is basically a non-issue as you'll never not be riding a meat puppet.