Would be nice for climbing to have a grappling hook or even a rock tried to the end of a rope for climbing and before anyone asks yes, please if the rope touches a fence or any anticlimb device the cord will sever as would of course any damage to the player.
Why would you not use a rope to climb over an edge or other dangerous incline or simply a place with no good hand holds (RL in know but valid in the sense of angle of climb that the game still seems to have trouble with at times). Climbing ropes would do also a lot in avoiding so much emphasis on high up bases and more on practical on the ground bases and maybe spur more development on ground base defenses to the game.
Well, for right now I would figure just a simple weight limited rope that uses a similar mechanic to the elevator except that you are the power (stamina limiting) moving you up and down the cord. Knots and or loops could be added the rope for grip and help with stamina loss and maybe some recovery on the way up (different tiers of ropes).
The ropes could be thrown short distand with a weight attached to the end. Others could be fired by a bow, but length of rope would be a factor on how far and how high you would be allowed to climb.
I guess if the game coding allowed it swinging grapples could be added too.
The remember same rules for climbing apply like mentioned in the OP.
You killing them or hitting them on the way over and maknig them fall, fences, thralls, pets, spikes to hit on the way down, and of course ceilings over the top.
Also, sorry I forgot this and need to add it this. Falling distance would be issue as well if the climbing rope or cord wasn’t long enough to go all the way to the ground or surface they need to get to or they wanted to the later ( if even possible) swing in approach as fall damage would be a factor and spikes plus fall equal big hurt as well.
You can also make spkes not only for falling on but also so they hit them from the side on the way in and down from the swing and if the hit the side and down on a spike from enough height you get to loot their corpse.
This I personally suggest it more of a flat rate in that if not instant destroy then only a second or two because too much can be done even in that long.