I can confirm this issue.
For the past two hours I experienced increased amount of "lag" while using abilities, etc.
If I check the statistics ingame, it only shows me the usual 30-40ms.
Looking at the information page of Warmane, it tells us that the current latency is roughly ~400ms, so definitely seems on their end.
Interestingly, the issue only seems to exist on Icecrown - if you get into a battleground, the issue is gone. Probably because all battlegrounds are on their own layer/server.
Lets see if this will get resolved quickly (:
Can confirm aswell, I came to the forums to see if there was something being said about this. It's sort of an "invisible" lag, it doesn't show in the MS status but everything takes 1 or 2 seconds delay, tried to do a dungeon and the healer was having trouble keeping the group alive because of this. I have also noticed that there are a couple of spots in icecrown were there are inmense FPS drops. I think somebody may be doing something intentionally that causes the lag and the fps drops.