Lol no, Hitomi plays nothing like Ein. And no, Ein is not in the game.
Technically to me, she does, but does not have his full move list, just a bit modified here and there.
She's missing some rather significant moves-- like Ein's P+K and 6P+K, which I mixed up for all sorts of mind games. 7K is also a great counter-attack that cannot be held (and even better when it started air combos, pre-nerf). Also, her damage is lower across the board in exchange for higher combo strings, which changes the way I play her. With Ein, I'm much more defensive thanks to 7K and the various P+K moves (only one of which Hitomi also has), which do tons of damage as a counter-hit. Hitomi lacks those options, so I have to go on offense more.
So, yeah. I'm missing Ein, my main in DOA4. That's the only DLC character I can see myself paying for.