Perhaps not on the
Morrowind/
Oblivion level of literally hundreds of hours' worth of side- and subquests to undertake, but some extended number of non-main-quest-involved missions would be quite a welcome addition to the
Zelda series. That bar has since been raised, and the producers now need to clear it.
One of the few things I truly enjoyed about
Majora's Mask were the side-missions, and given the ungodly amount of time
TP's been in development, it's not inconceivable that we'll be getting at least
that number of sidemissions to perform, or as many as were in
Ocarina of Time...and more still would be even better.