As a lot of people seem to be making up their own Rogue class ideas I thought I'd share some.
Rather than do reasonable/probable ideas, I thought I'd make something so incredibly OTT and then can scale back from there to something a bit more reasonable. (all these are assuming Combo Points are now on the Rogue and not the target)
Assassination :
My Assassination idea comes from the failure at the moment for Poisons and bleeds to really mean anything in game. I can put stacks of "Deadly" poison on someone and rupture them, and they run around as if they're not even poisoned at all! WTF?
My idea thus is for the poison damage to actually be LOW, but to have a longer duration that's refreshed on each application and for their damage to increase by a larger degree for each stack that's applied.
The same with bleeds, they would be stackable and would cause a decrease in the healing that the target received. The idea is that Assassin Rogues would almost have a soft enrage. You have to kill them fast or you'll slowly start to get so much poison built up and bleed so much that you're HP will just get eaten through as if you have run out of fatigue.
Assassi will build points with Mutilate, then Envenom will add a stack of "Lethal Poison", which will start off as strong as deadly poison, but on each stack the poisons total damage will go up by 20% (So for 4 stacks you have 4*LethalPoisonDamage*180%) and their speed will be decreased by 5%. We'll give this a cooldown of 60 seconds and, screw it we'll let it stack to 40 (I did say it'd be ridiculous).
As their stack got too high the player would also start to experience the drunk/groggy effect to.. because being able to hardly walk as your health is nosediving isn't bad enough.
There will also be a talent called "Hunting in Packs" which will enable any Rogues in the group to share the same stack of Lethal Poison.
Subtlety
For Subtlety I'm going to focus on the stealth and Shadowstep in particularly. Actually this is going to be more of a shadowstep build.
Sub Rouges can update Shadowstep so that it now has a cooldown on individual targets rather than on it's own.
Once you have used Shadowstep you will be concealed by stealth for 0.5 seconds or until any damage has been carried out on the target you stepped to.
As soon as you have Shadowstepped to a target, however, your ShS cooldown on all other targets is reset!
I am very aware that this may start to get pretty X2 Nightcrawler crazy pretty quick and become bloody hard to even catch a Rogue but therein lies the fun! (for Rogues)
Other skills for Sub :
When you Sap a target, they become stealthed and you unstealth taking on their appearance. All players view you as if you were their former teammate but can still target and damage you.
I'll update when I have time for some Combat ideas!! Combat is more about Control, with some stuns and the ability to jump onto an Enemys shoulders and stab them in the head while they run around, like that Goblin in the dead-mines.
ooh and a Rogue Glyph, while I'm at it :
Glyph of Dual Wielding : Your Off hand weapon now visually appears identical to your main hand weapon