I do not understand this statement at all.
Nintendo has ALWAYS brought new people to make their IPs from time to time. Not one single time have they ever decided to let their older staff to develop games.
There are always new programmers and graphic designers who come and go every now and then. That makes them completely new to such work.
The new producer behind the Mario series isn't actually Shigeru Miyamoto nor is it Takeshi Tezuka. Its actually Yoshiaki Koizumi.
The director behind Metroid prime isn't Yoshio Sakamoto, Hiroji Kyotake(who's the creator of Samus btw), or Makoto Kano. Its an american called Mark Pacini.
Heck, almost every Kirby game after Kirby's Air Ride has different producers and directors here and there as well as different people working on each of those games.
Tell me the list of people who have been old and still do the development and decision making for each and every Nintendo IP out there. The only ones I can think of are Xenoblade and Fire Emblem but that's just about it.
To simply say that new blood should come is just stupid. New blood or old blood really doesn't matter because at the end of the day, the decisions of making and directing games in specific forms is what matters.
And for those going to argue that Botw is made by new people, wrong. The directors behind the game have worked for Nintendo for years and years ago. So does that mean that they should quit because that "New" blood is needed?