Xpac for dagger pvp?

hi guys

i'm looking for an xpac where dagger rogues are viable
i realy like the theme about daggers, using backstab, having to be behind the enemy

so, what xpac would you suggest or has the most potential in your opinion?

Vanilla, BC, WotLK and Cataclysm all are fine with daggers, not sure about anything past Cata. There's a difference between viable and optimal though.

Vanilla: Rogues are really good with daggers vs low armor targets, Hemo is a better all-round build though.

BC: Mutilate is viable and is exactly what you describe: daggers + positional requirement. Shadowstep is simply better though. There are also Ambush/Backstab Sub/hybrid builds but they are basically world PvP fun specs and not viable in Arena.

WotLK: Mutilate is viable but has no positional requirement. Subtlety using daggers is also viable and quite strong if you know how to play it.

Cata: Sub with daggers is by far the most powerful PvP spec for Rogues this expo. Mutilate is also very strong but again, no positional requirements and Mutilate is so easy to kite that it's garbage vs Mages/Hunters/DKs.

TLDR: BC is the worst expo for Dagger Rogues (viable but comparatively dagger Rogues are weakest in BC), Cata probably the best. I'd advise going with Cataclysm because in WotLK your day will be ruined by Shadowmourne and Wizardcleaves. Find some Reckful videos on Youtube and you'll see what I mean.

Your only real choice on Warmane is Wotlk. Cata/MoP are dead and BC gimps you for using daggers.

seems like i have to settle with wotlk

and ty for your answers!