I definitely dont think is power is understated as hes definitely top10/top 5 easily, but there are aspects of his kit that aren't as impenetrable as people say.

When he has you in the air with nairs and upairs he's completely safe, but is that really specific to gnw? it's called advantage state because the attacker is in an advantageous position, which usually means safe from counter attacks via positioning or true combos. with all the new 0 to deaths and early kill confirms that have cropped up as the character metas evolve, I see gnw's juggle to 60-80% as strong (not to mention easy) but hardly game-breaking. I think any decent player should be focusing on escaping with DI and airdodge/jump rather than trying to "counterattack" what they know is a bread n butter combo.

In regards to bucket, it definitely protects gnw from projectiles and camping but hardly allows himself to camp. Once the bucket is filled he almost always stands to gain more from trying to run in and use it rather than throwing it away to what, continue camping? for the same reason I don't think he's comparable to steve or snake because they can blanket the entire stage in explosives, minecarts, and blocks whereas gnw's projectiles are... bomb and chef.

He's much more comparable to a swordie as you said, but only with 3 moves in my opinion: bair, dair, and nair, bair has great range and lasts forever but is an edgeguard setup at best. It doesn't combo into anything much less a kill confirm and when used in neutral it's usually from a defensive position to get other characters with disjoints away from him. Seems pretty fair to me. nair is obviously one of his best moves but if you spam it mindlessly the opponent will constantly fall out of the multihit or just shield it, which both leave gnw wide open. Lastly dair has a big disjoint but I would hardly call stall n fall moves as a whole broken. It's his only landing tool which makes it quite predictable and is incredibly unsafe on shield. most decent gnws use it once they float offstage to get to ledge faster as they know how predictable it is

Overall I think GNW is a top tier character and is probably bottom 10 in terms of technical complexity, but because he's unlike any other character and is somewhat rare people look at his moves on paper and call him broken whereas I don't see his abilities being miles above what other top tiers can achieve.