1 Disagree. The attacker knows whats gonna happen and can plan accordingly. Defenders should have the advantage.
2 Disagree. Defenders are forced to actually defend their fiefs with army's instead of just pumping into population, thats why i like the possibility to raid. Maybe limit the amount of loot to 100% equip of the army stationed, and 50% of all thats left after that (population gear). If you want to use the chest system like you suggested i would always attack towns with 500 man, since its impossible to hold the complete map and thus you always take a good share of their loot.
3 Disagree. If you retreat it means you didn't perform good enough to win the battle. Defenders was locked down for 24h, if attacker can't win it he should lose the battle.
4 Agree. Plains should be actual plains. On top of that i would love to see a weather system added to the strat map (clouds moving around the map, representing certain weather conditions, that way you can plan on what conditions you want to fight. See rain coming? Charge out to your enemy with only meleegear. Enemy castle is very good for archer? wait for rain or snow or whatnot and then start an attack)
The "defending is OP" problem of strategus comes only from the looting system + battle time limit. The flag capping is great as it is, and reinforcement window too and prevent fiefs being taken too easily.
1st. Defenders would still have the advantage in fiefs, because of the fortifications. They shouldn't have an advantage just due to the fact that the attackers can't kill enough of them in some arbitrary time limit.
2. What's the point of having population then if they're completely useless to defend with? Forcing armies to sit in fiefs is boring.
3. Yeah if you retreat it means your losing the fight and want to cut your losses, now you lose everything making retreating completely pointless and useless as a tool.
3) Difference in opinion. If you lock someone down for 24 hours by attacking him i don't think you deserve any compensation other then the win or lose loot you will get.
2) Population does still make sense. If someone attacks you, and you have no army in there, you make sure you already have the gear on you. In 2 hours the attacker will have it known as a raid or a siege.