Lots of good ideas in here, few not so good but I agree with most of the ideas here.
My one addition would be for a MMO standard style Auction house. The one in XI was ok Id gladly take that(Tho to do this you would also need a mail system). Now dont take the market wards and retainers away. In any MMO there is always a street or area where a flee market of people setup a bazaar and sell what they could not put on the AH. Keeping the market ward would save people from having to leave their accounts logged in and PC's on for god knows how long. This would save some bandwidth also.