There's a place for brevity, but not in this paper. You are assuming somehow that there is redundancy in the paper. There doesn't seem to be, at first glance. The scope of the paper is large enough to merit the length.
I'm not assuming redundancy, i'm assuming what every academic does - that the author(s) should be able to concisely and accurately present their work. There's plenty of examples where complex ideas and derivations can make the journal page limit (which does vary, but i think 16 pages is good), no reason this one can't as well.
