My biggest problem with Tears of the Kingdom is the Sages' Vows. Yes, really. The abilities on their own are really cool: a horizontal wind gust (perfect for getting a contraption going); a one-time shield that you can throw off a la Leaf Shield (helps with some of the more annoying bosses); a fast spindash projectile with low cooldown (wasting durability on ore deposits no more!); and a precise and powerful lightning strike. The catch is that you have to walk up to one of the four hologram sages and press A, and then press A again, and then do the thing. Also the noises they make are annoying, and they make combat encounters even more mindless than before. I don't mind mindless combat, I'm a Sonic Heroes fan for crying out loud, but when the AI kills all the enemies for me before I can even get accquainted with what's going on, it's just really annoying. And trying to activate a Vow during combat? Lol. Don't even try. The Sages' Vows are all seemingly for the sake of giving Link companions to fight alongside, which I can admire for story reasons, but it just doesn't translate well to gameplay beyond small novelties. Still, you can turn them off so it's not a huge deal for me.
The vows only make sense in three scenarios - gliding with Tulin and driving with Yunobo (since it's automatically on the ready), and Mineru's mech (you activate it same way as a horse which makes sense). Everything else though, I never use.
My problems with the Vows were further amplified today when I got the Earthwake ability. Without a weapon equipped, hold the attack button and you'll send a small crater forward, and when you let go a rock spike comes out. I've found it perfect for dealing with low-health monsters like Stalkoblins and the little frog things in the Depths. No need to waste my weapons or arrows on them anymore, and it looks awesome! Now, imagine how much more fun that would be if it had a 7 second cooldown, and was activated by a green Master Kohga who follows you around and "helps" you fight monsters, but makes a really annoying sound every time you start or stop gliding or climbing a wall. Yeah...
So why not just have the Sages' Vows abilities be more passive, like Earthwake or the Champion abilities of BotW? When you start aiming an arrow, Ruji appears alongside you and there's a prompt to press A - if you do, she activates the lightning field. When you're shielding, Sidon's shield appears, and whiffing a parry is what makes it fly forward. Tulin's is activated by holding X (same as Revali's), and maybe Yunobo's is activated upon performing a dash attack. And since you can turn off the Vows, none of these would be a nuisance. Also, just have the Sages float around Link instead of following him on foot, or just make them appear whenever there's a combat encounter or whenever one of their abilities is/can be activated.
I know you can turn off the Vows but I don't think that means I shouldn't complain - it's still a missed opportunity, and one that I'm constantly thinking about whenever I have a Sage's Vow active in TotK.