There is a clear issue with "ganks" on the server.
With ganks being deep trenches with fence gates and traps that let defenders get to safety but don't let attackers get out in case they end up inside (like one-way valve but for players)
The biggest issue with ganks is that its very difficult to get any melee combat kills near the banner as attacker, as defenders just have the option to jump into the gank and force you to either double down on your intentions to get a kill and jump into "inescapable" trap or just give up on the kill.
Personally, I do not have a problem with it, because none of the siege mechanics make it necessary or unavoidable to pursue any melee combat further than chasing the enemy away from the banner chunk, which is perfectly achievable even with them not dying and just escaping into a gank
but what i constantly see happening in EVERY siege is people constantly fighting melee fights in front of walls and in wilderness around the town (or even in front of siege town cause some people are just so hellbent on chasing kills that its not uncommon for defenders to end up being attackers on the siege town) so the ganks are clearly the big issue regardless
I do not think the issue with ganks is "mecahnical" in nature, as it does not obstruct, overshadow or turn any of the existing game mechanics irrelevant.
meaning that in a "perfect world" where:
Defenders ONLY stay on the walls and leverage their defensive advantages (cannons, guns)against the attackers by defending the walls
Attackers only attempt to breach the defenses and take control of the chunk by sieging the walls with movecraft, climbing them and forcing defenders off, to allow themselves to capture the siege chunk
ganks would not be an issue at all, they simply don't play a role in such cases.
But in practice it does not play out like that.
So my possbile fixes for the ganks could be :
1. )Fall damage immediately tagging you in combat if you are inside a siege zone, while you can not open doors or use elevators in combat.
(this makes you on "equal grounds" with your enemy if you do end up jumping into a gank to prevent combat from happening in the first palce.
2.) Any means of preventing fall damage need to be removed, so falling down from 24 blocks ALWAYS means death. this includes acrobatics skill rolls and Protection enchant counting towards "feather falling" If it is possible to make it impossible for players to reduce fall damage (as if you are only wearing unenchanted diamond armor) then anyone who jumps into a gank will just die by default and there is no advantage in doing so. (this also means that water should stop working towards reducing fall damage in siege zones if people catch up to it and start making workarounds)
3.) This one might be "controversial" but allow the player to instantly /tpa (within the allowed range) even in combat with no delay within 20 seconds after killing an enemy, its certainly a big thing to consider and it does allow people to escape PvP, but i only see it relevant in instances when:
1) you do decide to jump into a gank because it secures your kill and you end up trading a kill for kill because by doing so you end up trapped and killed and the enemy turns your otherwise "sure victory" into a draw.
2) when you simply know that if you do end up getting a kill you are most likely going to get killed anyway. This is going to remove any advantage the enemy may get by jumping into a gank, making you give up on following up for the kill and letting them survive.
So by being able to immediately just tpa away after a kill is going to make the ganks less effective at discouraging you from killing the enemy. Also this is probably not going to play any role in normal combat as most of the times you do not die within 20 seconds of killing an enemy, and even if you would die, its difficult to organise someone to tpa you out if it was not planned in the first place. (and when you jump into a gank you do plan to get out in the first place if it is as possiblity)