There's just too many unknowns about what the game will be like post-TBC for me to invest the time in leveling up a Human Rogue alt.
This is what bothers me as well.
In the near past I got the impression that Blizzard was trying to push the dagger rogue somewhat relative to the sinister strike rogue. If this trend continues in the expansion, then being nightelf may actually be the better choice, albeit very slightly.
However the current state of the new talents does not have me excited very much either way (I am seriously pondering if I should try 21/0/40 in the expansion). Combat dagger rogues either pick up seal fate or go 41/x/x and loose DW Spec or Opportunity, Sinister Strikers best option is probably 30/31/0. Some additional changes are probably coming.
Also I got the impression that while in the past combat dagger and combat sword and played very similar (which made it easy for Blizzard to balance the two) now Blizzard actively tries to generate a different gameplay style for each weapon type. I would not be surprised it the new and revamped 41pt Combat talent would favour swords/fists/maces. In that case I would probably favour the sword gameplay.
Being a human would be the safe bet, since in PvE you loose very little (relative to Nightelves) if you go daggers but gain a lot if you go swords.