Inspired by the Blooms game mentioned in another post (2-player 4-color go ā« āŖ šµ š“ - #18 by LuisB), another interesting variation upon the rules would be to eliminate players only when X of their stones have been captured.
I think it would change the dynamics of the game quite a bit, with different natures across different sizes of X. Fundamentally, it is still a territorial game, but now the players would have more freedom and incentive to make a smaller sacrifice to help capture a larger group.