It has been a long time since I really played a pvp thief in fel, but it was a lot of fun back in the day.
A few questions/comments though.
1) Have you considered or do you already include RP/pvp thieves? I have an RP thief that I've been very heavily considering taking to fel and getting back into the real thieving world.
Though I will admit, I too am not such a fan of the persuasion thief, I'd probably lean more towards spawn thieving.
2) When it comes to thief taxes... Again from the eyes of an rp/pvper...have you ever considered doing thief taxes a different way?
For example:
I have played atlantic for years now, but my home shard was Napa Valley. One of my most fond memories was Adam Ant, probably the most successful RP Pk there has been in my eyes. If you entered their dungeon and they found you, they would offer you a red bandanna. If you took the bandanna and wore it all was well, if you didn't however, they were going to kill you. Sometimes they didn't even offer you that, they just attacked, because after a while everyone on the shard KNEW that if they were without bandanna they should expect a fight.
So having taken from that, even if it is just as much a borrowed concept as joining/robbing guilds...
What if your thief tax was more of something say related to champ spawns? Pay the thief tax or our team of thieves are going to rob every scroll you get while you do all the work for us?
Just throwing thoughts out there.
I guess that is all I have for now.