Gail, Barry, and Elliott have put it very succinctly.

If you really want slightly different performance from one of the system procs, create on of your own that fills that requirement or suggest a mod or new one be created to MS. If they find it to be useful in widescale, they may make a change or create a new one for future release. Emphasis is on may. It never hurts to ask - but take it to the owner of the product.