User blog comment:Kogath/Monster Hunter XX Discussion/@comment-26034899-20161027225642/@comment-3298463-20161029150156

I don't know why they make so many flying wyverns, maybe that's why the Japanese fanbase wants (do note, however, than Seregios is noticeably different to most other flying wyverns when it comes to attacks and animations; Astalos not so much, but he's supposed to be a kind of "anniversary" counterpart to Rathalos). I don't know why they don't make more Fanged Wyverns, maybe they don't have ideas or don't want to make Zinogre "less special", so to speak, though it's about time they added another one. Najarala has a very special skeleton that's huge and already kind of wonky, perhaps they're considering revisiting it in a future or maybe it's more trouble that's it worth. The Carapaceon skeleton is super outdated but I could see them reusing it somehow in future games... maybe.

But favoritism is totally an excuse, they're not under any obligation to make more amphibians or temnocerans if they don't want to. I hope they do though.

I'd say Crystalbeard is the exception rather than the rule, as Grimclaw, the Raths, Deadeye, Silverwind, Thunderlord, etc. are sufficiently different from their regular counterparts. Crystalbeard is pretty much G Rank Uragaan from 3U, I agree.

Ultimately this is pretty much just spitballing and I don't have much insight into Capcom's development practices. I guess more people will buy a game if they're promised a new, improved version of an already popular monster (Zinogre or Nargacuga) than an improved whatever (Cephadrome or Basarios or some other unpopular monster).