From this thread in suggestions is the idea to have a PVP map with limited or no consumables. This would force competitors to more carefully manage their health and sp during fights.
Post in this thread what kind of restrictions you would like to see.
There are some logistical hurdles to implementation which could prevent this from working properly.
We are not able to set item restrictions on a map by map basis. In RO, restrictions on what items can be used where is set by map type. Town maps, field maps, dungeon maps, etc. The number of these is limited and many of them are already used for special maps
Having an NPC check and reject players with certain items would be more possible, though it would be crucial to block kafra cards as well as consumables
We cannot remove effects already placed on players before they enter the PVP room