I have to admit. I was not expecting a trailer like this that exclusively talked about the competitive aspect of SwSh. It's oddly refreshing and I hope we see more trailers like this down the line.
Galarian Weezing's Neutralizing Gas looks to be a pretty good Doubles ability, but it could become a double-edged sword for your own Pokemon. In fact, they even showcased this downside in the trailer when they demonstrated the removal of the partner Rotom-W's Levitate ability so the opposing Gastrodon could take it out with Earth Power. A part of me feels like the benefits gained from removing the opponent's abilities may be eclipsed by the negatives of your ally's abilities being disabled depending on the situation, which leaves me to believe Levitate will still be the more consistent option. I could be proven wrong, though. As for Singles, I feel Levitate would still be the better option by far.
Room Service is pointless, you’d much rather have an item that does something more than let you win the TR mirror matchup.
I was going to say it'd be good for faster Pokemon that are trying to use Trick Room to their advantage, but then I realized that Iron Ball already exists, and is an item that
halves your speed indefinitely. With that, I have to agree with this one unless Iron Ball is somehow not in SwSh.
Eject Pack sounds like a neat item, although I question why I'd use this over an item that increases attack power like Life Orb, Choice items, etc if it ends up being single use. If it can be used more than once, this'll be an extremely powerful tool for Pokemon like Hydreigon who like to use Draco Meteor.
Breaking Swipe looks to be about as good as Snarl is, but on the physical attacking side. Main difference here is that it can't go past subs, but Soundproof mons aren't immune to it.
Corviknight's Mirror Armor is neat, although I was hoping for Intimidate as the hidden ability. Good news is that if Corviknight has decent set up moves like Swords Dance (it's at least confirmed to have Hone Claws), opposing Intimidate users can't lower its attack after boosting, and are actually punished for trying to do so. Given how excellent of a defensive typing Steel/Flying is on the physical side, this is a nice perk for Corvy.
I'm happy that Dynamax/Gigantamax mons can't be flinched. Given their limited battle time, that would have been a pretty cheap way to kill that mechanic, especially when going for Protect afterwards.