Michael - you do not sound too convinced about my enlarged island!
I agree that a 1-phase crossing sounds great, but unfortunately tfl prioritise their red route traffic over all other considerations.

If a 1-phase crossing stops the traffic for twice as long, then they'll keep the people waiting to cross... twice as long.
And then they'll wonder why crowds of pedestrians are forcing their own way across, some stranded half way...with no island.

To keep pedestrians' wait reasonable for a 1 phase cross, and to keep the flow of the south circ similar to now then I think the Dartmouth Rd exit (straight ahead) phase is again going to have to be sacrificed.

There are no easy answers with tfl in charge - I'll keep you informed if I get a vegan cardboard bus to negotiate around my island.