To start, the three most popular concerns seem to be:

1. Vanish not properly functioning in certain situations (though it does work very well a majority of the time)

2. Combo points not always being registered. (I believe this has been fixed on the test realms)

3. Lack of usefulness in high end raids such as Onyxia and Molten Core.

4. Poisons disappearing after entering/exiting instances.

5. Thrown weapon balance vs. bows/guns.

6. Eviscerate consuming 35 energy on a miss rather than using up less like other abilities.

And as always well-thought out and reasonably presented arguments are most welcome. :)

[update]

Players, this isn't a discussion to add functionality or more power to rogues. It is a discussion to see what is not working as intended, and to correct it.

[update2]

The usefulness of daggers/backstab builds is being increased in the upcoming patch, so dagger discussions will not be considered here for the time being.