I'm actually not a student of film, I'm a student of computer imaging and studio arts. I've just taken as many film complimentary courses as I could, and from those courses I can say its not where I'm the most talented. It also doesn't help that in a lot of cases I even attack my own work in front of the class if by the end I wasn't able to get it right. My partners are often not very pleased, though by the end they learned to accept it.
Anywho, I think inevitably all movies are what they are. But thats not a reason to say something is a worthy addition to its genre. As a ninja film, I guess it fits in because most movies primarily about ninjas usually end up being nothing special. And in the end, to bring up the Asylum again, its like saying Invasion of the Pod People was better than the average film of theirs. It may be better, but it really doesn't mean much as its still inevitably not very good.
And really, compared to Japanese samurai movies featuring ninjas as side characters, Ninja Assassin gets blown out of the water.