I know, UIApparence should be the way to set fonts everywhere, but that defeat the purpose of rapid prototyping IB is made for.
(but yes, I agree, that it has taken this long is crazy)
Can't you just use an attributed string? Xcode lets you pick a font using the standard system font picker then.
A word of caution, though. Using key paths in your categories like "fontName" is pretty dangerous. Apple could add such a property, or your users could already have one on their object, that would cause problems. I would suggest including a prefix or suffix, e.g. "cvs_fontName" similar to three-letter-prefixing.
I'll second the mention about checking the release notes of the latest iOS/Xcode beta, for those who have access. Moarfonts seemed promising, but caused nothing but problems when we tried it.
I can't figure out why that's an issue though — URBImageMediaViewController (dependency where the error comes from)'s sample project doesn't link against Accelerate.framework either, but it builds fine.
Any reason for the iOS 7 requirement?