No, please don't do that!
I was all for uncapping usernames, since they are prone to each and every user's personal spelling preferences and styles. But those general headings are not to be uncapped. Afterall I wasn't too satisfied with the fact that uncapping the usernames came with uncapping all the other captions, like "Top Questions" and the like.
The all-caps style of captions is inherent to the style of this site, as also evident from the site's logo text, which isn't "Movies & TV" but "MOVIES & TV". And I think this all-caps style is fitting very well to the topic and the rest of the site's style as detailed in its initial motivation. And it also helps to customize this site in a design framework that has already gotten more
rigid standardized than it once was. It doesn't really make the reading of those captions much harder, I think. So no, the all-caps style of captions fits perfectly well to our current desing and is not to be changed except for user names.