-After you place a ram on a wall, they are immune for 24 hours
At some point in the process the attacker needs a break. This is the break which, hopefully, will make the prospect of sieging more appealing. The rest of the idea is based from this attacker relief.
-The owner of that wall, can then set a timer for that ram, for when it will become vulnerable to attack
The defenders advantage enabling them to avoid getting screwed by a bad timezone. It's up to the attacker to make an effort regardless of the time. You want rice with that chipotle? Sorry, you actually have to fight koreans now.
-Can only set a time that is longer than 8 hours. If a time is not selected, it will just become vulnerable after 24 hours runs out
8 hours is a decent minimum time giving both sides an opportunity to react. The defenders can ignore setting a time, but this won't delay the attack indefinitely. Both sides know when its time to party.
-Once it becomes vulnerable, the ram must wait 2 hours before it can be used
You have two evils to choose from, because even with timers, there will still be rushing. Between a village getting rushed or a ram getting rushed, the latter is preferable.
-Rams can only be placed directly on a DRIED wall. Gates are off limits
This is to prevent trolling BS that can result from making new walls. Unless rams can be made non-collidable then they really don't have any business going on top of a gate or fresh wall. Even if they can have no-collide I suspect its simply easier to check the wall properties.
-Rams can be inspected to check what time it will be vulnerable
Saves everyone involved the hassle of shitting themselves worrying when it will be ready. You know that altar timer check you made? Might be cool to implement it here in some form.
-Stake and village claims will have a new option for allowing their selected friends to choose a time of vulnerability for a siege ram
Would be very nice in the player-interaction department, but not critical to the core concept. However, the vulnerability timer should be decidable by at least more than one defending villager. Allows for more synergy between defending forces.
-Rams must be attacked for one minute before they start taking damage
The less influence shitty naked alts have, the better.
-Ram cost should be increased
Compensating for the prospect of invulnerability. Hard leather costs are the most obvious, but the other resources can be increased to deter spamming.
-All of the notifications ALL OF THEM
Where possible send information regarding a ram. Most importantly - a village or claim owner ought to receive some type of message that they are under attack by a ram. This message should be repeated in some form, perhaps on login or every 2 hours
Something extra for you to think about before the reset. Enjoy.