What stage was that?
I'm always dreading stages with Giant Bosses, Gohma is a jerk who runs too fast (I once ended up being chased by the [dark hold] for like 3 minutes in a stage where I had to get 700 KOs in 10 minutes, all because he either did his charging attack or walked at me and never his laser.) King Dodongo has too many shockwaves and his AI doesn't like to do his weak point attack, Manhandala goes [tornado fang]ing berzerk when its health gets too low, Imprisioned is a retarded Muppet and I don't like his shockwave spam either, the only one I can fight with any consistency is Agorok because he almost always reveals his weakpoint.
As for characters, I've not unlocked Zant yet but I'm most proficient with Link (Either because the Master Sword is great and SwordBeams are broken or because he's at least 10-15 levels ahead of the pack.) and I enjoy using Zelda, Impa, Midna, Lana and Sheik.
Most of my issues with the other characters stem from a mixture of low levels combined with being stuck with weak weapons (Seriously, if I have to unlock Agitha, Ruto, Ghirahim and Zant, wouldn't it be better to start them on levels higher than [tornado fang]ing 20-25?), I've only just unlocked lvl2 weapons for Darunia, Ruto and Midna and the game continues to give me shitty 0-star, 0 skill lvl1 weapons on them (Well, Midna's been fine weapon wise) so I haven't been able to really use them that much, my Zelda amiibo just keeps vomiting up Royal Dominion Rods, which while nice aren't really going to help me do much of anything considering how unwieldy it is. I'm having extreme frustration getting Materials especially from other characters or bosses because the game is more willing to spit out worthless weapons than it is to get anything else. I'm mostly trying to grind badges since those will take longest to do anyway.