>The enemy has to be fun to shoot at, as well as be shot at
If they were going to start with one thing, the aforementioned would be my recommendation. Nothing in BotW or TotK (or really any 3D iteration) was fun to fight, and that cut both ways, in the sense that the player's mechanics are not particularly fun as much as they are functional. In other words, it was barebones. Not to mention how terrible the enemy design was. Everything, including Ganon/dorf was a pushover, and heaven forbid you actually somehow lose, you just respawn with no consequences.
Wandering around war-torn calamity didn't really feel like the fight for survival it was sold as, both mechanically and thematically; calamity occurred, but nobody in Hyrule seems to care lol. The tone felt like walking around Sesame Street.
Anyway. Fix that stuff and then you can look to maybe hiring somebody to fix the level design, puzzle design, writing, and score.
>tl;dr
It's easier to list the things that don't need to be fixed.