Nelf is undisputed bis rogue race, but to consider your question:
I take gnome over worg any day.
As a rogue time on target is obviously essential. In this regard escape artist is just as if not more valuable than dark flight. Concussion shot, frost nova, priest/druid roots, conflagrate, crip poison, pet pins and slows, all render dark flight useless or force you to sit the cc, take more dmg, and then catch back up. Rogues cant afford to extend time in combat, shorter fights tend to be more successful. Escape artist allows you to instantly break those slows/immobilize effects on a short cd to get back on target and land your finisher/kick/control. Its no contest imo.
An additional benefit worth mentioning is that a large number of players don't use nameplates in pvp. Especially in congested fights that require a lot of attention to different friendlies and enemies, the gnome rogue can literally hack away up someones butt without being noticed. Certain player animations allow gnomes to almost totally disappear within the legs of enemy players and adds a unique advantage that occasionally turns the table in your favor.
Other thoughts worth mentioning: rogues are not starved of crit. Crit scales poorly in pvp anyway.
With WoD on the way weapon expertise passives will be replaced with something!? That something could be just one more reason to gnom gnom.