I dont for one moment believe thieves are overpowered, and even if they are. SO WHAT! anet already said they weren’t going to balance in the same way WoW was. Guild wars 2 is the best balanced game i have ever seen.
I have 7 80’s, everything except and engineer. My guardian, and necro cank ill thieves easy. and all other classes have a niche. Thieves can be beaten if you change you’re playstyle. adapt and you will win. Complain to change others so you can win…. and finish the sentence yourself.