I agree with the previous speakers that an customizable Ui would be really nice. I heard a lot of beginners say that they would love to have an "post imperial age" button in the TC in the imperial age which costs as much as the combined non researched technologies and researches all of them at once if you click on it...
What I personally always wanted to have is a spy unit. For example, it could cost 500 gold, look like a villager and can do nothing but walk. However, to another player it looks like one of their own villager, until they click on it.
The first idea is good, it doesn't add anything to higher level game play but seems fun for newbs.
The second idea is interesting, could be useful if the spy could work at resources but didn't extract any of them.