IMO the main problem with these FATEs is that probably no one wants to sit in a zone forever camping it just to get a chance at doing it.

They could mitigate this issue by adding something to the weather checker NPC or some sort of "Town Crier" NPC that has a zone wide prompt in Foundation like the Gold Saucer ones that will notify you within 1 hour if Royal Levin or Hyperelectricity is going to spawn in the zone(s). That at least cuts it down to an hour or two of waiting and makes it way more accessible.