Sequential turns are unbearable and simultaneous is bad for the metagame. Personally I can't even stand hybrid, when it turns into sequential turns. I usually end up just using simultaneous despite its problems. I feel like you should be able to do everything other than purchases (units, buildings, policies, beliefs, etc) and unit movement/actions out of turn. I want to be able to do stuff like looking at menus (or the civilopedia), changing tech and production queues, deals with other civs etc. I see very few significant ways to abuse this and I feel like it would speed things up in addition to giving you something to do during an opponent's turn. Basically, excluding deals with other civs, if it has an immediate effect you can only do it in turn. If it's just changing a queue order that wont take effect for a bit then you should be able to do it. Anyone see any issue with this?