In another thread, starting at Suggest a new rule you'd like to see in Go (fun times) - #70 by stone.defender and continuing for at least a few posts after that, @stone.defender proposed a new variant that I think captures the spirit of Capture Go, while still retaining life and death similar to regular Go.
I think the rule changes (building off of some common Go rule set) could be summarized as: score the game by comparing only the number of captured stones, but break ties with normal scoring.
Note: passing is allowed in this proposed variant. A peaceful game with no capturing will be decided by area, territory, or stones (depending on the underlying common rules selected), but a game with captures would be decided by who captures the most rather than strictly first. Once a player has captured more stones and can easily secure life for their remaining stones on the board, the game is effectively over.
I believe that life and death (except for maybe really odd cases) would mostly behave like normal Go. Throw-ins to disrupt eye shape, snap-backs, and sacrifices are now possible tactics to deploy.
Any one want to try a test game?
Edit: completed a test game with @jlt: Capture go variant