One thing that is definitely pending to be improved is the auction system. Not by the auction system itself, but by the items that are generated throughout the server. Especially in the middle-end and WW stages the auction system is completely dead and practically the last interesting bid is given by the natar's horns. Thus, in the end of the server, silver coins only end up being relevant to be converted into gold and, therefore, the missions that reward in silver also become irrelevant.
I remember, not very well, that a long time ago there were artifacts that generated certain types of benefits (in attack, defense and const. times) for the kingdoms that were fighting in the WW stage. I.e this kind of items can be included in the auction system and they'll add another variable to the WW strategy.
Also, currently existing items need to be developed to a T.4 .