I've considered dropping him as well at one point but he's just too awesome for me to do that. He might be limited but I still believe he has a lot going for him.
@Zeo, unfortunately not. I've come up with even more tech since then. It's just the way that DOA5 was designed. It doesn't benefit Ein the way DOA4, and 2 did.
While's he's extremely bad. He's a character that will keep your fundamentals at a higher than average level, don't drop him, use him to cement your playstyle with your main.
I know I can't say much maining Nyotengu. But, other than her being the best suited me, I just play through pure character dedication and find more ways to make use of what she has.