Technical support is available from the staff via the ticket system and players who wish to participate via the forum. The staff no longer reads connection tests, which is what I explained. Instead, they now have a general connection troubleshooting article for all players, like every other gaming company out there.
You’ve reported it, that’s good enough. It doesn’t look like lag is listed on their known issues post at the time of this reply. I wasn’t able to replicate the problem in Dalaran on Illidan or Area52, but it’s possible other servers are running into an issue. Since it’s Day 1 of the prepatch, I recommend waiting for communication tomorrow, if they have something to share.