JetSetter on 04 December 2015
As you mentioned earlier, Aonuma has been spread out pretty thin this generation so that might be a pretty reasonable explanation. Plus, you also mentioned XCX being similar since it was announced in 2013 and it kept getting updates but hell these didn't really start until late last year/early this year. There was a long period for silence regarding that title and for SMT x FE (now #FE) as well. The only way I can explain this is that Nintendo had some internal goings-on this generation that caused stuff to be put on the back burner while somethings got straightened out.
But hey I'm just happy that this isn't a Last Guardian situation all over again.
