The suggested idea sounds ok, but has it's drawbacks:
1. The initial game would be fun, but if one island has a quick dominator, and the other does not, it would be a definite win with boredom.
2. The hardcore mode would be pointless, since the vortex would be the only gap between them, ending in most scenarios in a draw.
3. The space around the vortex without capture, would not make too much sense either. There would just be an obstacle by the vortex.
Finally, as I recall,
Lopdo wrote: <...> I don't plan to add extensive changes to the gameplay <...>