Quality>Quantity. Momiji, for example, actually quite a nice selection. Could use a few more, but not bad. Leon's only got a few, but the ones he does have are excellent.
Yeah, Ein probably has it the worst out of everyone. One good costume, one meh costume that used to be good. One awful costume, one "MY EYES" costume and one costume that was almost awesome but they decided to unzip the shirt and make it look excessively gay.
I think Eins only good costume is his karate costume. Just because it's the only one that doesn't make him seem gay. At least Ein is back. That's something for the Ein fans.