The lag issue is the number one priority: It would take away a huge amount of frustration if the server did not go into epic lag when large numbers of people logged on, or lagged for other mystifying reasons. This effects so many things the players do.
For example if I am picking branches, without lag there is a neat steady rhythm so that I can stop the process when I have enough branches in inventory for my construction. With lag it's anyone's guess how many seconds the procedure will take or if the branches will be visible when they are supposed to be and I have to guess when I might have enough. Half the time I either don't have enough or that one extra branch that has to be dropped.
Hunting is another thing that lag makes aggravating. Click on an animal? No, sorry, it actually moved a few seconds ago.
Crashes - I am assuming this situation is related to the lag problem -make overland travel totally frustrating. Portages have a nasty tendency to return you suddenly to hearth fire, minus boat and cargo, of course.
I could go on listing reasons why this is a significant impediment to play, but that would devolve into this being complaint, rather than the explanation for my opinion. I suspect we could make a long, long thread supporting this viewpoint.
Anyone here who disaggreees with me about lag being the number one priority, would you care to post your rebuttal here, and why?
I would be more than happy if all other development stopped for a month until this was thoroughly addressed. And this is although I live for those exciting new developments every weekend...