Years ago, I submitted a bug report to Apple. The problem? Teeny, tiny subtitles in the iOS Videos app, so small that even an eagle with binoculars couldn’t read them. I got a mail from Apple to follow up, and then, just one or two releases later, subtitles got big enough to read (the Lady and I have different native tongues so we usually watch everything with subs).
Now, in iOS 7, they’re not only big but completely customizable.