I highly doubt this issue is on ISP's end because I always get 10 ms ping on speed tests and all my other games run lag free, including different MMO's. Its definitely something caused by this latest update.
It's not your ISP directly, it's the route that your data takes to get to the servers and back. i.e. it's a problem between the ISP and SE's servers, not between you and your ISP. Some ISP's use different pipes and routing tables, and from what we're seeing here it seems like Verizon (and my Australian ISP) is routing through addresses that are not in the best of health. Eventually this kind of thing gets sorted out, the routing tables updated, and you get a decent route, the Christmas break is probably slowing that down somewhat.

I do agree that it seems to have been caused by the latest update though, I have never seen anything like this before 2.1. So, something they've done with the configuration of the new datacentres seems to have caused the routes to go bad, either by changing them to different ones or overloading the existing ones with traffic.