As an avid Real-Time Strategy fan who grew up with great classics like Age of Empires, I have always loved the little details present in the gameplay. Something that I'd love to see in upcoming editions is an increase in information that is available during the Edain Mod gameplay.
Something that I always like to study for fun when I'm playing is checking on the health of units to see how strong they're getting as they level up. I've always been set back by the information that isn't available to me though, which sometimes leaves me scratching my head. While hero units have health and damage values to see, normal soldiers only have health to see. It would be a bit helpful to learn more about a unit when I hold my cursor over it, such as armor value, speed, damage, range, and damage bonuses. The more I know about a soldier, the more I can be made aware of how to utilize them in a situation.
Another thing that would be helpful is for there being a better after-game statistics page. Measuring the unit number, building number, resources number, and score number is fine and good, but I've always found the charts to be a bit vague. For instance, the "Fortress" thumbnail that sometimes appears there isn't too helpful. Is it that I built a new camp/castle, or is it that I built an outpost? Better yet, I'd like to know how the score table works, like what actions increase your score and what things decrease it. Computer players always seem to have the higher scores all of the time, and it gives me a warped impression that they're always better than me for whatever reason.