Powerplay requires densely populated regions of space to be "profitable" and power expansion. Colonia is a collection of low-population systems thinly spread out across a fairly large area. If you transplanted the Colonia star systems to a region of space just on the edge of the Bubble, no Power would want to expand into it - it's simply too expensive. For a Power to gain any traction in Colonia it would need to work under radically different rules to that of the rest of PowerPlay. And to what end? So that unarmed explorers who happen to be pledged to a Power get blown up on arrival in Colonia?
Nope. Bad idea, that one.