Characters walking into the city seem to have no particular problems, but those using a portal such as the one in Undercity or in the Pandaria Shrine, appear to be having issues. On attempting to confirm this, the portal from Undercity was used.
I monitored my frame rate across Orgrimmar, onto the Zeppelin, over to Undercity from Brill and out of the portal room in Silvermoon to the scene you see in front of you. You can see the results of this to the right-hand side, the 31 FPS is when I first arrived in Silvermoon, dropping to 10 when I stepped outside the portal room itself, then to four, and then stabilizing at 2FPS, where it remained for 15 minutes until I was unceremoniously disconnected. A second attempt with no addons revealed the same results, though marginally higher frame rates.
Silvermoon is very graphically intensive, and I'd turned my graphics down from their usual Ultra to Good in anticipation of issues like the ones experienced. On logging back in after my disconnect, I had a framerate of zero even with lower graphics settings, so dropped the quality to Low, which gave me a framerate of 6.
I don't have an incredibly powerful computer, but it's pretty hot as far as laptops go, so I can see this causing major issues for other players.
What do you do if you get stuck? Option one is to try to hearthstone. Another possibility is to walk to the bottom of the red carpet in the header image, where my frame rate jumped from 5 to 108 on Low graphics settings, and stayed there. If you can get to that point you may have the same experience. Lastly, if you can open the game menu, click on Help, then Character Stuck, and teleport to graveyard. If your hearthstone isn't working, this may not either, as it has a cast time.
Of course, an easy fix is not to use a portal to get there, but that's easier said than done if your character is in Pandaria!
Mists of Pandaria is here! The level cap has been raised to 90, many players have returned to Azeroth, and pet battles are taking the world by storm. Keep an eye out for all of the latest news, and check out our comprehensive guide to Mists of Pandaria for everything you'll ever need to know.