I think the only force that could ever be omnipotent in Homestucks universe would be if all 12 Lords of all 12 Aspects came together and did something.

Yep. Each of the Aspects is a facet of reality, it doesn’t matter how much control you have over one Aspect- Unless you have full control of all 12 Aspects, there will always be something that eludes you. I mean- 12 Muses would work too.