Board Thread:Episode Discussions/@comment-3125844-20131220190508/@comment-24265987-20140107164449

Bob the Wikipedian wrote:

Well, Marie did say there are more kinds of Wesen than had even been encountered by Nick's ancestors-- to me that implies there are many yet unknown to the Grimms. well, yes, as also are diferent language speakers and different ethnicities, but that doesn't mean you will meet all of them in your live; just as there are millions of animals species you probably just will know so many.

And, to be clear, the problem is not that much they introduce lots of new wesen, but why they introduce them. In many cases is not even necesary the introduction of a new wesen as the story could work with the ones already exist. In a show is important to mantain coherence that there's a reason for each decition.