I'm not sure why CA keeps on promising better siege battles in every game in the series. I think a better approach would be to change the game rules to have more open field battles and less siege battles. Personally, I will always prefer and enjoy open field battles compared to siege battles no matter how much improvement sieges get. Not to mention most of the most memorable historically important battles were open field battles, not siege battles.

Siege battles will always be harder to implement and code AI for. I'm not saying ignore it because it's a part of the game but something tells me that spending more time trying to change the ratio of open field to siege battles is a better use of resources.