Gates, as SecDef, has been pushing for many of those changes since he took office in 2006. There's quite a bit to give Obama credit for, but Gates as SecDef is not one of them.
Patently false. Gates introduced these changes in April of 2009: http://www.cnn.com/2009/POLITICS/04/06/gates.budget.cuts/ind.... I'd be interested in any sort of proof that Gates was working on changes like this during the Bush years, because as I recall, programs like missile defense were being expanded not cut during that time.