The guy is not calling the game bland but rather its visuals, at least that is how I read it.
And you know what? I kind of agree even though I own the game. The Switch is rather dated these days, has been since launch really, and while Nintendo's ambition and flair for great game design is ever present in this new release, it is hard to not feel a bit underwhelmed by the graphics which haven't really improved at all in the six years since Breath of the Wild. Normally, when you compare sequels from opposite ends of a console's life cycle you can see clear improvements to all aspects of the visuals as graphical techniques and coding evolves and developers master the hardware to milk more out of it. Not so with Switch because it was already a limited system at launch.
And, yes, I get that there is more to game sequels than prettier graphics but I really hope that Nintendo's next system is at least powerful enough for basics like anisotropic texture filtering and anti-aliasing (features that have been around for years on other systems but yet remain almost alien concepts to Nintendo) because the absence of those coupled with the sub-1080p resolutions of most of the Switch's games makes them a real eye-sore when played on a 55" 4K TV. Even the OLED screen can't hide all the visual shortcomings which is a shame because in terms of actual art design, Nintendo rarely disappoint. It's their hardware that does. The last console they released with competitive hardware was the GameCube; since then they've gradually fallen further and further behind the competition.
Incidentally, I played more of my 160+ hours on Breath of the Wild (Wii U version) on my PC via Cemu, where I was able to not only enjoy a smooth 60 fps framerate but also improved visual fidelity with less aliased shadows and longer draw distances that really enhanced my enjoyment of the game. It was hard to go back to the Switch version after that. While I own Tears of the Kingdom for Switch, I will be looking at playing it on my PC via yuku if I can and only playing it in handheld mode while I am at work. I am quietly hoping that the Switch's successor will be a 1080p hybrid handheld and console system with a dock that has additional hardware to display the graphics upscaled with better image quality for 4K TVs. This dock only really needs to be as powerful as the PS4 or even PS4 Pro to achieve this and it would make playing games on TVs a lot more enjoyable that it is currently with the Switch.