I'd say your best bet is to find powers and spells that had effects you could use in myriad different ways. Polymorph/metamorphosis, psionic dominate/charm, astral construct, time hop, psionic minor creation, fusion...
Think about how many ways you can use it, then use it.
I could easily make use of a high-level manifester who only had a single psionic power, and the power points to manifest it all day long.
Don't ask what you can do for your countryfor your powers. Ask what your powers can do for you.
As far as metamorphosis/etc goes, you don't have to use it for combat forms. It's great for utility and sneakage, as well.