Breath of the Wild is, frankly, the first Nintendo game aside from the Xenoblade titles that actually feels modern since the Gamecube era. Nintendo has been sticking motion controls into game templates from the GC/PS2/XB era and passing that off as "innovation" for ten years. Breath of the Wild is more the direction that the rest of the industry went, though with the Nintendo touch that makes it unique and, frankly, better. It's where I wanted Nintendo to go in 2006 but they didn't.
This seems a bit harsh to me? Splatoon really fits with the whole Team Fortress/Overwatch thing that's popular, and I'm not sure the motion controls there are shoehorned into an early 2000s concept. With Star Fox Zero I could see that comparison perhaps... But I mean, Nintendo
have been bankrolling pretty complex HD games: Pikmin 3, Wonderful 101, Bayonetta 2, and none of those sold well. The motion controls in Metroid Prime 3 were hailed as great for immersion, and maligned in DKC Returns (not a "gimmicky/casual" title either), and those are from the same studio.
If I was a business and I see triple-A game production sales down across the board, then chasing other crowds seems more logical right? And you could argue Nintendo's recent best-sellers were titles with broader, more casual appeal (Yoshi Woolly World cracked a million sales) - the hardcore gamers aren't there in terms of sales it seems.
Idk, I'm not saying you're wrong, but just because Nintendo aren't showing the type of innovation that many gamers want (more titles like BotW), doesn't mean there's just zero innovation happening. For what it's worth, I don't really wanna see Nintendo follow the whole Dark Souls/Monster Hunter trends or whatever too much, so I hope Zelda's success lessons will mostly stay within the Zelda and Xenoblade franchises. Bad example, but I don't really want Mario Odyssey to suddenly ramp up the difficulty because "it worked for Zelda".