List of game mechanics and bugs that hurt the strategy:
You know that a building is located in some fog zone because your selected construction turns red indicating it. The game has always been like this and this is a way of knowing about the enemy without fully exploring the territory in the game, it is anti-strategic and unrealistic for this type of game.
You see deer in the field in fog, worse, you see them dying when hunted by the enemy. This is another way of knowing about the map and enemy movements without exploring the map. The deer on the mini map is fine, but seeing it in the fog is wrong.
You can hear things in the fog, so… pls… no sounds in the fog! This is wrong, but some exceptions could be accepted as cannon blasts, because indeed cannons were heard “beyond sight” and over great distances.
Units do not move or take alternate paths when the enemy make a wall, even without the player having explored the wall. The correct one should be for the unit to move in a straight line until it finds the wall and explores it.
And for last… don’t blame the players if the game have so many bad mechanicis for strategy and bugs. Recently a player was excluded from a tournament for taking advantage of these bugs that have been in the game for a long time, so… it’s the game’s duty to solve these issues to make the game fairer for everyone!
Video about that: Laughing on AOE's 4 Top 1 player tears - YouTube