Kabal wouldn't change much at all with this, unfortunately. Sure, there's the aerial gas blast that could lead to some insane stuff, but it's really the only other move that he doesn't have competitive access to that would be worth a damn.
I think people would probably opt for Extended Hook (restand), Hook Grab (db2 launcher) and MAYBE Dash Cancel if not Gas Blast. If anything were to change, you'd probably see his air dash coupled with Hook Grab if the player can do without the restand from Extended Hook/Gas Blast.
Low Hook? Unsafe. Leads to nothing. Pass.
Low Buzz Saw? What is this even in the game for? Pass.
Parry? Never even touched it, so I have no idea about how viable it is. Likely a pass.
Dash Cancel? Not worth the cost of a defensive bar when being +2 and not being able to really do much with it. Pass.
Low Hook Spin? I see this used more as a combo ender than extender in most cases and can likely be done without. Pass.
Straight Air Buzz Saw? Give me the utility of his normal air projectile any day. Pass.
Nomad Spin? What is this even in the game for? Pass.
Gas Blast? Good for keeping yourself safe, is a restand and can be used to heal yourself when amplified when not used on block/hit. Can be a viable option.
Air Gas Blast? This seems like the biggest game changer for how Kabal would play in its current state. I haven't put much time into it and my execution/creativity is sorely lacking, so I'm not the one to find out its potential. While it likely wouldn't lead to pre-patch levels of Upgraded oppression, it may allow Kabal to be extremely annoying. If Kustoms were ever allowed, I'd expect this to have the biggest presence over anything else provided it doesn't end up being shit.
I'm fairly certain Kabal isn't the only character that would suffer from not much, if anything changing with a Kustom loadout that's better than what's already available.
I'd be for this, but it would be a balancing nightmare. No joke. Almost everything would need to get some sort of an overhaul to either tune it up or down for competitive use and we see how well NRS did with that with just the addition of third variations.
I don't have enough faith in NRS to pull this off successfully. It would probably cause a lot more harm than good in the grand scheme of things. People are clamoring for a balance patch and that's just for what's currently competitive. Imagine NRS trying to rebalance 50~ abilities to be used competitively all at once. I'd rather not.
But hey, maybe that's why the patch everyone wants is currently taking so long (I'm also factoring the pandemic into this as well): perhaps they're trying to balance everything for competitive use. That's just wishful thinking, however. I just hope if they do this that they do it right and don't turn it all into one giant clusterfuck.