The pose of the silhouette doesn't really matter. If you look back at all the previous professions/elites, there are a few of them that the pose doesn't match. For example, look at Necro, Reaper, and Scourge. All three show a different pose. Elementalist and Weaver have two different poses. In fact, with Elementalist and Weaver, the Weaver pose looks a lot more aggressive in it's stance. But, as @Jski.6180 said, we will know more on the 13th.
https://wiki.guildwars2.com/wiki/Necromancer#/media/File:Necromancer_03_concept_art.jpg
https://wiki.guildwars2.com/wiki/Reaper#/media/File:Spec_image_Reaper.jpg
https://wiki.guildwars2.com/wiki/Scourge#/media/File:Spec_image_Scourge.jpg
https://wiki.guildwars2.com/wiki/Elementalist#/media/File:Elementalist_04_concept_art.png
https://wiki.guildwars2.com/wiki/Weaver#/media/File:Spec_image_Weaver.jpg