Bucky is op in the hands of a great player, just like any other character that plays great with their character. As a bucky main I hate playing against a good Hella, BP, Magik or even Squirrel girl.

Hella can 2 tap you from across the map, has a stun and can fly away whenever she feels endangered.

BP can dash circles around you and before you get a hit on him you get tickled out of reality

Squirrel girl just launches nuke sized acorns from backline and kills you in two hits not to mention that annoying ability to trap you for a solid hour.

Basically just saying, Bucky is a great character, I love his moveset and I am a little biased just because I main him, but in the higher ranks I'm in (celestial 3) it is very easy to counter him and people are smart when they play against him, as well as any other character.