Reworking Frontline was on the timeline for after Rival Wings was it not? Honestly the easiest fix for this IMHO is to remove Onsal Hakair and Seal Rock for now That way square doesn't have to think about how to balance pvp for Crystalline Conflict and also older content that doesn't work with the new PVP design philosophy.

Until SE takes some sort of formal action I guess report people you see doing it for Nuisance Behavior. The people who are doing this in Frontline matches know that this is obstructing normal gameplay.