PO is a card that requires you to build your deck in a specific way which narrows your deck and in turn opens you up to hate. If players want to beat PO they can do that easily because PO narrows your deck down hard.
Gush is a card that is closer to treasure cruise and DTT than a card like PO. It's almost never dead. It doesn't open you up to anything, and it incentivizes a playstyle (low land count, cheap spells) which doesn't have any particular weakness, but tons of benefits.
Gush is a much more dangerous card and is much more likely to be on the restricted list because it's so much harder to fight. There is no null rod or stony silence for gush so if a gush deck becomes too strong, Wizards probably need to step in which they already have - just like they did with cruise and DTT.
This is exactly what just happened with DRS in legacy. DRS deck were winning too much and players couldn't find a way to attack DRS because it didn't have any apparent weakness so Wizards had to step in.
With PO Wizards don't need to do anything, the players can fix the deck by themselves all they have to do is play less shops, more fair blue, and include some stonys/null rods.
I think vintage is in a great spot right now. There is no deck or archetype that wins too much. Players can choose to play combo, aggro or control and no matter what they choose they will have a tier 1 available to them. I can play a bunch of different fair blue decks, shops, dredge, a ton of different combo decks and I don't feel like im gimping myself for any given tournament.
That in my eyes is a great format