This is a tandem discussion along with whether monsters should be able to utilise their full movement speed found here https://forums.elementalgame.com/426091 , I think both should be implemented 
Basically would allowing monsters to target outposts and cities and improvements make the game more fun. Currently according to the Sir Frogler, monsters do NOT target outposts or ciities or improvements, but accidentally destroy them if they get in the way. I think they actually avoid city tiles.... I tried getting a elemental army to attack a city by getting agro then running to the other side of the city. It chased me, but instead of heading directly through the city, it went around it to get to me. Anyways, below are hte benefits and negatives of allowing monsters to target cities and/or outposts and resources
Pros:
- no more pioneer spam early game. Anything created by a pioneer all by itself would get destroyed shortly without protection
- increase the early game exploration and cleanout era a resonable amount (this bit is lots of fun!!!)
- If released monsters were allowed to target offending outposts and cities, they could be set to go back to guarding their lair once the ZOC has been removed.
- Better defined territories of the players, because you won't be able to plop outposts or cities in distant locations right next to some monsters that haven't been cleared out. I'm looking at you AI city on the OTHER side of my territory relative to your territory, right next to that SLAG MONSTER!! Better defined terriotry makes for better wars, as you jab and feint trying to get through their armies defense (assuming powers are equal)
- Force humans to have multi layerd defense, better equalises power between human and AI. (can't run around with 2-3 uber champs and expect to control much territory).
Cons:
- If roaming monsters aren't reset to guarding lairs after they destroy ZOC offending structures, then releasing them early could be a game break (MASSIVE NEGAITVE FUN). Imagine home city being target because lazy AI pioneer got an outpost next to that Drake stack....