Pretty much everything that can be said about it has already been said at this point so I won’t beat this very, very dead horse. I’ll just keep it simple:
Corrosion would be far too difficult to balance at this point and this just isn’t the project for it. It should be removed.
There are two abilities on the slate that I really, really like, and I’ll start with
Water Bubble, which I love. Y’all have probably seen my posts about it and how much I love the idea of a defensive WB user. Keep it slated.
The other ability I really like is
Stamina, which I think could very be nice for 30b. Getting a progressively stronger defensive presence that also gets offensively stronger with a gradually strengthening Body Press is cool. Keep it slated.
Fluffy is alright I guess but I’m not a huge fan of the Fire trade-off, at least in this meta. One reason I like WB so much is because of how well it targets and checks

,

, etc. Fluffy’s physical muting is very cool, and the Fire weakness certainly helps to balance it, but it just doesn’t appeal as much to me personally. I wouldn’t mind it staying on the slate for variety.
Not too keen on
No Guard, since I don’t really like the idea of 30b stepping on 30i’s toes (if it even has them lmao) with such an overtly offensive ability. And like others have said, it kinda encroaches on anti-concept territory since

used the ability so catastrophically and so recently. It can stay I guess? But idk, I don’t love it.
Thick Fat is an ability that sounds great on paper but I feel would be lackluster in practice. The Fire-type resistance is nice and does help our matchups with

,

, and

, among others, but I personally disagree with the notion that TF would do this better than WB. Our Ice matchup is the thing I’m iffy about. Unless we have some crazy bulk as it is, I don’t think TF will really be a gamechanger for 30b’s matchup with prominent Ice types like

,

, and

. All of these mons have very strong, borderline nuclear Ice STABs, and I don’t know that TF will truly help with this in the long run. Provided we’re able to successfully turn OHKOs to 2HKOs, we’re put in an unfavorable position where we either get some chip or a Toxic off and then get hit again and subsequently dropped like a fly, or we hard switch and something else that gets chunked. If this is the biggest selling point of Thick Fat but it ultimately can’t do that very effectively, then that speaks for itself Thick Fat can stay slated I guess but I don’t think it’ll truly be that great in the long run. It’s also less of a worry but I do kind of wonder if it encroaches on anti-concept territory since

used the ability very effectively only a generation ago, but that may be kinda reaching.