Zapdos is a great addition to the UU tier, I love it so much. It can wall stuff like Cobalion no problem while also being able to defeat bulky waters and bulky Steels with Heat Wave. It also has a lot of versatility in it's sets, like offensive LO, offensive Defog, defensive, Specs, Scarf, etc. It does have a slight case of 4MSS though, as said above, as it wants Volt Switch and TBolt, and HP and Roost and Defog depending on the set, so it has at least has a flaw, along with being weak to SR. But it has many positive traits, including synergizing well with many of the tier's top threats, like Mega Swampert and Feraligatr (who is worse now but still powerful). So, yeah, while Zapdos isn't any way broken in my opinion, it is going to change a tier a bit. (Imo, a good starting rank would be A+, and then let's slowly see how it works and see if it's S or not.)
Oh yeah, and I think Mega Abomasnow is gonna be REALLY good now, even if it already was. It crushes Zapdos + Swampert/Mamoswine cores if Zapdos doesn't have Heat Wave, but the slight nerf to bulky waters in the wake of Zapdos might hurt it a bit.
Zoroark with Sludge Bomb seems interesting, it can hurt Fairies now, so it might get a bit more viable.
Overall, UU is going to change a bit, and I like it! Finally, my favorite Kanto Burd is back, and he's ready to wreck!