I strongly believe that modern Nintendo has become a barrier for Zelda's evolution.
Nintendo games have become conservative, unambitious, casualized and, instead of pushing design and technology like they used to, are trying to get away by putting too much emphasis on gimmicks.
Nintendo's modern approach on gaming may be fine when it comes to games like Animal Crossing, Nintendoland, or Wii Sports, but Zelda is a franchise with different needs.
Maybe I'm giving Nintendo too much slack here, but it does seem to be a bit like their fanbase is at fault here. Everybody saying that they're not going to buy a Wii U unless Mario 523 or Zelda 482 arrive, with NSMB games massively outselling the more inventive 3D Mario ones and Zelda forums basically being collections of long monologues how Zelda needs to be more like that user remembers it. Of course Nintendo needs to be more paternalistic in this (you don't know what you want, here this completely new thing is what you really want), but it's hard to argue with economics. Luckily the times seem to be a changin in that NSMBU seems to have impressed absolutely no one.