what? against who? I'm pretty sure that ninjas would try to avoid a "fair fight" as often as possible. They were assassins, not master fighters or soldiers. Many people forget that a ninja was primarily poor and ill-equipped, unlike a samurai who trained years and years to master his craft. Ninjas weren't people who trained on a mountain top for 20 years like in a movie or something.
Also, to answer the original question.
I expect to see the katanas to make a comeback, other than that i think that most ninja equipment would feel out of place.