While a 3rd *A status level would benefit me personally (have 2 top *A statuses), I do quite like the current setup. OW is a lot smaller than *A and really only has a few F lounges - whereas on *A F access for top elites would be a disaster.
Further, but not having to provide additional *A benefits each programme is free to choose its own extra benefits for the top *G level and some of these are rather generous.