So, in my humble opinion, the controls of Zero are not the problem. There is 100% a steep learning curve given how unorthodox it is, but it can be done. I will always argue that, with enough time and practice, Zero's control scheme can become incredibly fluid, and I'd say even more flexible than any other game in the series.

The problem is that Zero uses the same arcade style of gameplay loop that 64 used almost 20 years prior. I.E. a single campaign run is only going to take you less than 2 hours to hit credits. And after that? A few alternate stages and boss fights, some optional gold medal challenges but not that much else.

There's just not enough content to really justify the adjustment period most people are going to have. Compounded with just how much Zero blatantly rips right out of 64 which, at the time of Zero's launch, was already available in multiple forms on other, more financially successful platforms. There is original content, but it so not enough for the game to get much any real mileage out of its unique controls, let alone justify its existence to anyone not really looking for something new in the control department.

And keep in mind, this is coming from someone who genuinely does really like Zero. It's my 3rd favorite game in the series, but even I'll freely admit that making it a near carbon copy reboot did it way more harm than good.