First off I was talking about angeling obviously, as holy light is their only offensive spell. Wear angeling + usakoring and priests can do 0 to you. Stave will do poop damage, holy light will miss. This leads to the conclusion that basically 1 card completely blocks this class and thus it's not an viable option for pvp, At least not unless you're in a gang. Second of I'm not complaining about the class, you are.. so I'm not seeing what you're trying to do here. Thirdly, priest's magic attack will never reach as high as a prof's one neither does priest have the elemental boosts that prof have, and thus stave crasher is even weaker on priests than it already is on prof's/ wizards. Out of all magic classes profs are by far the strongest on FRO so no, we should not include professors.
It'd be better to look at how we can improve other builds instead of nerfing existing ones. This would be extremely easy to beat. Having fcp + gtb makes you completely immune to such a clown/gypsy. TAO RSX/Pneuma/gtb = Immune for any gypsy/clown, unless you make a mistake and get out of pneuma. Clowns NEED the effect of all tarot cards, that's their playstyle. You need to be able to force people to gtb because their regular damage is way too low. And they need to survive until they coma or are able to get lucky and burst someone down.
You should stop assuming other players haven't fought against this. Yes it might be annoying but it's not OP in any way and thus balance wise it's fine. You don't nerf things just because people find it annoying to fight against.. I've played against a LOT of ninja's in the past years on this server and I don't really have problems with any of them. They're easy to counter and now that they can't warp anymore they are also easy to kill. You just have to know how to fight them :).