The 338-06 needs no "improving" IME... been there, done that. Great round.
If you want more than the 338-06 get a 338 WM. Been there done that too.
The 338 WSM is a nice oddity... have certainly shot Dobers, but the reality is it's a poorer feeding 338-06+P that holds less down. It's not as good as the 338-06 or the 338 WM IMO... FWIW.