I think this is more geared towards action themes or Castle themes, where your average Joe is equipped with a battle axe and thrown in the midst of battle. For those occasions, I think the more "stern" expressions are useful, and completely appropriate. However, if some random City janitor had an angry face all the while, and the mailman looked as if he was shouting, I could see a very small reason for complaint. Not even touching upon the fact that most of these faces are double-sided, with a expression that reflects a more happy mood on one side, and the "stern" expression on the other.
As far as increase in weapons goes, as a TFOL all I see is "New parts!" but from a parent's perspective, I suppose it could be seen as encouraging violence or what have you. Not that I agree, though. Mentioning BrickArms is completely irrelevant, as BrickArms is not affiliated with TLG in any way, shape, or form officially outside of the fact that their products are LEGO-compatible.