Didn't see any rule breakage so I thought I'd come here. I downloaded GIMP to edit a texture and when I went to load a texture file from the .bsa, it couldn't find it. Is this because of a new version or something?

I don't believe GIMP has the capacity to read .dds files. I generally use http://paint.net/ for those.

Figured it out, you have to download a plugin

http://cs.elderscrolls.com/constwiki/index.php/DDS_Tools#GIMP_DDS_Plugin

FWIW, I've had better results using GIMP to edit in a format it's happy with already and using a converter tool afterward. Most things I need to do with a texture use layers during the process and it's useful to save a version that keeps those, to make it easier to re-work things when you're not quite happy with the result. So I save as psd (Photoshop's format, which is well-supporeted by other tools) and convert that to dds externally.