I posted a reply in the general forums but thought I'd repost it here as well-
As many players have noticed, we have made a slight change to the male Blood Elf character models. In response to concerns that the Blood Elf male appeared to be too feminine, and after reviewing the model from a visual and conceptual standpoint, the decision was made to increase the body mass to give them a more substantial, masculine feel. It was also important that as members of the Horde that the Blood Elves gave the impression of strength and a more menacing presence.
Please be aware that all beta content is still subject to testing and can change at any time.