I realize that, but there was PvP outside of Darktide, with the same problems. Most of the common complaints can be addressed with PvP itself. The major exception is disabling housing.
lol famous last words. Someone will find a new way, or step up all the other exploits that had already been used to stockpile the broken stuff well before. If the items are there, the motivation is there.
If there are rare buffs in the game, they could be dispelled by PvP combat, or just not work on PKs and PKLs. Disabling the gem's use by linking it to the old 30 second combat timer wouldn't cut it. Even without rares, there are numerous other buff items which can and will be abused, like the Harbinger protection gems, luminance crystals, and penguin eggs.
Ratings and high mods broke both PvP and PvE. Again, this goes back to much of these unpopular and problematic things not being unique to an all PK server.