Well I can't argue with your sentiment that it would make it easier, but then there's easier and there's necessary and right now it's not really necessary, I've operated from SOU airport off and on for 11 years and I've never once had an issue with the backtracking.
We go again - Reversethrustset is of course correct, there is a difference between what you want and what you need. Still to actually see any evidence of the delays caused by the lack of a taxiway, much less a business case.