There's really only two things you can do: ask for it directly and press for a good reason why not, and job hunt where that is what you're looking for (make it

There's really only two things you can do: ask for it directly and press for a good reason why not, and job hunt where that is what you're looking for (make it clear). I feel your pain. Legacy systems breed a laziness in me personally. Because I know at best I can make a 1% improvement here and there, so it gets less of my energy. Being new in a legacy thing can help, you come in with green eyes and start fixing things no one else thought to. But that runs out eventually.