Don't know if there are any other threads on this, but, having fairly bad connectivity issues since maintenance.
Wrothgar ping spiking randomly from 180+/- (usual) to 999+, others in chat having same issues. Some comments have suggested that it may be addons causing the problem, however my other half and I both play, and I have some addons and she has none at all, and we are both experiencing the same problems.
Spiking was so bad, that npc dialogues wouldn't load, mining ores was taking 10-15 seconds, and summoning my mount was awkward, again maybe 20+ seconds.
Greenshade can't load into at all from either Wrothgar, or Elden Root, both DC characters. Have been on loading screen now for nearly 10 minutes..
Euro player, ping is typically 180-200. No 'known' ISP issues.
I am no expert so I am not going to insult the ZOS team with my blind guesses, as I suspect you already know and perhaps this may be related to why the maintenance took so long?
Anyway, please get it fixed.