Stealth specced thieves are indeed easy pickings for us rangers these days due to RF, Sic ’Em and Taunt respectively.
Now, thieves that mostly forgo stealth in favor of shadow stepping all over the place can be a totally different story, because it can be hard to keep track of them. However, in PvP this is often not viable because they don’t kill rangers fast enough when the ranger has a more defensive setup. Personally I’m running Wilderness Survival and Nature Magic with a utility bar of LR, Sic ‘Em, and SoS in PvP currently. That in combination with #4 GS basically means that thieves can’t kill me 1on1 and usually just die to a well timed Taunt + RF combo. I’ve had thieves try and kill me all match long already, just to prove they are actually capable of it.
With that said, I have to admit I’m fairly bad at the game and there are far better players out there that easily beat me 1on1.