It baffles me that people think Ganondorf is better than Bowser. He has like all of Ganondorfs strengths but is better in almost every other aspect. Aside from some of the absolutely insane Ganons, I think the character is almost seen as good because of other people just being bad half a year into the game. Only see him falling. Essentially to me, the only things Ganon is amazing for, Bowser is still great for.
I think Bowser is the best heavy, and the next best ones would be DK and Dedede (pretty slept on). He gets juggled easily, but you could say that for many of these characters. But unlike a traditional heavy character he loses a major weakness in being slow, and instead of just being not slow, he's actually fast. The weight makes him extremely difficult to kill (moreso than anyone else), all of his moves are actually pretty good, and he has good potential mixups, decent combos, and brutal answers for shield and spotdodge. He's intimidating to fight against psychologically, which is outside the game, but a very real thing when applying good pressure.
Nair combos are pretty ridiculous damage, at higher percents leads to bair on a ton of the cast. It's the best combo since Fire Breath. Don't think I need to speak on that in this game. Up B OOS is an amazing tool, can punish even some well spaced aerials. Side B I'd argue is the best command grab in the game. It makes your opponent feels unsafe, even on platforms. Fire Breath / up B punish spot dodge brutally or safely depending on how confident you are one is coming. Dair and Down B while not spammable are super useful and can even condition opponents into letting you get the other one in many scenarios. If you condition them to shield, down b will kill nearly any character as early as 20. Fair is stupidly good offstage. We all know this though, I'm just brushing the surface, didn't even mention things like Tough Guy or his tilts. Despite clearly having some big weaknesses and poor matchups vs some zoners, I think he's high tier (maybe low high tier but still). He has some weaknesses but his strengths are so ridiculously good (and the best in the game, at that) that in a lot of senses they make up for any shortcomings.
Only disclaimer here is that someone said he beats every other super heavy in the game. I think he loses kinda hard to Dedede. There's a high level Dedede in my area who shares this opinion as well. He has so many tools to mess with Bowser and Fire Breath not reflecting Gordo like Flamethrower is really rough. Dedede is the one character I feel is super hard for Bowser to kill when playing well.