This post has been largely based on
Hyouhaku's suggestions
on page 13.
Add a quest, miniquest, or achievement which will restore the normal function of the wilderness levels for the player while cursed gathering. This benefit will be enabled by wearing a reclaimable reward item which is always lost on death - for example: a "blessed insignia". (Eg a level 138 will no longer be able to attack a level 3 that is wearing a blessed insignia whilst harvesting cursed wisps).
Reasoning:
There is no point for a low level to oppose maxed mains, when they cannot win. It is currently unfair and combat level diversity has been destroyed.
The blessed insignia will be lengthy or difficult enough to obtain, that cursed energy bot farming will remain more efficient to keep creating new accounts when banned, yet enable legitimate low level players to play the content without being unfairly disadvantaged.
= everyone can still kill bots, others play fair
The "curse" which the player receives by having cursed energy will be taken from the item and applied as a 10 minute debuff, given when interacting with a cursed spring (and refreshed with every interaction). A purple skull will be placed above each player's head who have the cursed spring debuff.
Reasoning:
This will prevent max level PKers from picking off every single low level PKer. Combat level diversity will be restored. It will again be worthwhile to bring your unique account builds, or low level mains to the crater. Additional benefits: Players will no longer be able to drop cursed energy in order to be instantly cured, as the curse is not tied to the item, but the gathering of the item. Similarly, scams can no longer exist which exploit trade and drop-trade mechanics, by giving an unsuspecting player cursed energy, making them teleblocked and vulnerable to all PKers.