2 – There is a prompt when you press the retreat icon on the battle screen that explains about being on the edge of the map and such. Now if you retreat from the “Esc” menu then there is none. Just noticed myself, and this is if not a bug then a small error.
3 – Devs already said there will be speed differences. A system somewhat like M&B has.
4 – Now this is a rare thing to me and did not manage to catch how and why it occurs, might have to do with video drivers but still looking for it. Had it yesterday a heavy one. The same game client run for full day on pause while was doing other things sometimes jumping back for a battle. In the evening the heavy UI delay kicked in inside the battle. It was time to go home so didn’t care much.