TBH, visuals would not make a bit of difference to me. In fact, I think the game is already a bit too visual heavy and any melee who raids would agree with me.
I've been talking to people who have either played or tried to play Rogues and asked them what made them turn away from them, and the responses I've gotten where pretty much one of two things.
Either the game play was too slow (always waiting for energy), or they are just too squishy for questing and such when 2+ mobs are pulled.
Personally, I can agree to a point with the first one. The second not so much, yeah Rogues are a little more susceptible to damage but that's why we have the amount of control we have. The only aspect of questing I do have a problem with (since I play sub) is the fact that unless I focus on keeping targets stunned I can't use my primary combo point builder due to positional requirements.
It's been said by multiple people already and I feel I must echo the sentiment that Rogues right now just feel too maintenance heavy. If I had to pick a single CP Spender that takes the most fun away from the Rogue play style, it would be Slice and Dice. Forcing Rogues to rely so heavily on Auto-Attack, and in turn poison procs just takes so much fun out of the class.
The only way Slice and Dice can be removed is if either energy regen is redone so that we have a higher base regen with slower scaling from haste, or lower the energy costs of abilities so that they can be used more frequently.
I would also like to go into a little detail on Subtlety Rogues specifically since they are the least represented Class/Spec combo in the game for PvE.
Come 5.2, 20% of Subtlety Rogues damage is going to be reliant on keeping Rupture up. Marked for Death will help with this, but for Subtlety, Anticipation is still the clear winner simply due to the fact that we can not guarantee that the target is going to die before we must switch targets again. Also due to Honor Among Thieves pretty much granting a CP every 2-2.5 seconds not to mention Shadow Dance w/ Find Weakness greatly favoring the double 5cp Eviscerate especially now that Prep is going to be baseline once again thus giving us a slight increase to Find Weakness up-time.
Hemorrhage is a must for situations and encounters when we can not maintain the positional requirement for Backstab, but it is still a huge DPS loss and the gap needs to be a lot smaller. Also, the bleed applied by Hemorrhage is nothing more than another unnecessary maintenance for Subtlety Rogues. Without the Hemorrhage Bleed granting Sanguinary Veins it honestly seems pointless and is just barely enough damage to be a net DPS increase overall.
One other side note I would like to throw in. Energy Regen mechanics for Combat and Assassination are to spiky. They need to be smoothed out a bit.