Slow moving NPCs and monsters will be addressed. What an understatement. I'd say that monsters have doubled their walking speed. Pets follow a bit faster, though. Good luck running away from monsters on a dial up. Hell, good luck getting enough distance between you and the monsters to get a spell off.
Issues with gate travel and going through T2A portals seems to have improved. The need to resynch with the server has all but vanished when crossing servers. Walking across land server boundaries, however is extremely jerky, causing rubberbanding. Once, I gated to an area near Yew, close to a server boundary. I was unable to see monsters on the other side of the boundary, even though I was only 3 tiles away. Expect some rubberbanding and bouncing around if you have a pet following you through a gate. Also, expect gates to spontaneously close on you once you cast them. While the gate will close on your side, people can still see it on the other side.