The worst thing about rogues for me is the lack of animation compared to casters or even other melee classes.
It may be a non issue for gameplay but personally I think that looks are more important then function, since you have to keep looking at your character all the time.
What I think will make the rogue a much more fun class to play is to add animations like the anime Sword Art Online.
What happens is simple and not really complicated to implement (at least that is what I believe). Whenever a player does a special attack the weapon they use glows a bit till it hits. For this to work it has to be like SOA where the animation goes off when your just doing normal basic attacks.
I'm sure people will say stuff like ''it doesn't add dps so whats the point'', well my answer would be that for a person to have fun you have to notice that your attacking. The only reason why I know I'm attacking on my rogue is that energy is preventing me from spamming my special attack but otherwise their really isn't something that stands out, even the special attack of assassin rogues.
I'm sure their are some other nice animations but their are limitations to WoW, it has to be something not to demanding since WoW is a 8 year old game. Unless they can allow temporary scratches on mobs I think that making rogue attacks stand out more is the best buff you can give.
There are a lot of MMOs out there that'll suit your tastes, such as Aion, RaiderZ (in beta) among various other anime-style MMOs with super flashy melee attacks. WoW combat has kept it's style since it's inception, it's not going to turn into an anime-combat-style MMO with flames and purple laz0rz coming out of the tip of your swords, ever. Rogues are stealthy, sneaky bastards, having them put on a light show when they're stabbing sh*t would definitely ruin the class for me, and I doubt I'm alone.
One of the issues comes with Slice and Dice making auto-attack so fast, that it eats specials animations.
In example, I'm using two fist weapons and the special animation is a shoryuken, but I almost never see it because the character is too busy auto-attacking. The red or green thing from Envenom, Eviscerate or Kidney Shot is barely visible as well.
But I'm not expecting any upgrades until the next expansion. Shadow Dance got a subtle animation and that was it. Shadow Walk has nothing (read signature), Shadow Blades is an old weapon enchant and SoC is Illidan's stealth from that instance. At least Crimson Tempest looks decent.