here's a bunch of things i'd like to see, though they aren't exactly revolutionary:
-the ability to play against custom civs
-different skins for different civs like in RON
-more uniquene units, abilities, buildings. EE2 was one the right track in this department
-territory control like in EE2
-special unit abilities
-technology research more akin to EE1. Wasn't a fan of EE2's research system
-maybe a game mode where building hitpoints are greatly increased, to promote slower paced games.
-regeneration of organic resources (animals, bushes, fish ect)
-a minimalistic interface (I thought EE2's was a bit overwhelming)
-minor map dependent native civs like in AOE3, and bonus resources like in RON.
-space maps for future ages like in EE1
-maybe be able to choose a religious or government type which confers bonuses or units
- good ai and detailed diplomacy, similar to what was in RON
- a "prehistoric" age would be cool, along with maps...could have extinct animals like woolly mammoths, sabertooth
-positive/negative terrain bonuses like in Kohan II
-greater variety in tree/animal species. make some animals hostile to gatherer units (like wolves or lions)
-heroes like in EE1, but historically accurate (i.e. don't give persians Assyrian kings damnit)
-I'd like to see some different historical campaigns, rather than run of the mill WWII/Crusades/Greek. Maybe some based on Byzantines, Russian or Spanish Civil War, Persia, 30 years war.
-I'd like to see a less radical rock/paper/scissors system than what was in games like RON. I want my pike to get bonuses against cavalry, but at the same time be able to hold off swordsmen in a pinch to a lesser extent. AOE II did well with this I thought.
-larger unit cap than whats seen in CoH/DoW/CoC type games. But I'd also like my units to have the ability to survive battles and gain veteran statuses, rather than constantly spamming new units like in RON.
-ability to capture certain buildings
-units able to walk on walls
-maybe some kind of morale system