Also remember that there's very little worry about "supporting" EPUB3 on older devices when it comes to text-based novels. So long as there is a fall-back opf (and they don't get ridiculous with their css), most EPUB2 engines will render them just fine.
I'm ecstatic to see a lot of the "EPUB3 is the devil!" nonsense fading away. It was like the ability to handle multimedia was somehow going to
force all EPUBs to include multimedia.
