Pop is currently used to guarantee a 3-gen by regressing the fuck out of the gen that is being tapped in your 3-gen. Because even at best case scenario (a gen at 99% progression) it is still weaker than current pop, it will not really be viable post-patch, specially because it will be unable to execute the function it is used for (keeping a 3-gen will not be possible because your pops are only worth the effort on near-completion gens, and by that point the 3-gen is done).

Jolt and Pain Resonance will probably be the best passive regression. Right now they compete with Ruin for "best passive regression", but Ruin will not be a thing after the patch, and Jolt is getting so many buffs it will probably be king numbers-wise, and by a wide margin.

They all behave in different ways, though. Pop is just going to be garbage because it will not help you put a 25% gen into 0%, it'd instead go into 17.5% which is not even worth the trip. PR gives you a decent regression on a good gen (because it's always on the most progressed one), Jolt has the potential of giving you tons of regression, but it's nearly impossible to direct it in any way - hell, if you hit a good gen with Jolt you can already consider yourself lucky.

It's possible that pop can still see some use paired with something like Call of Brine, since you're going to go and kick anyway. Tbh gen kicker meta seems to be full of "all the perks that involve kicking gens!!!", which is dull as fuck. I'll personally stick with PR/Jolt since I hate kicking things and I don't want to purchase Sadako.