The audio plugin is very complicated because it covers four audio APIs (HTML5 audio, web audio, phonegap audio, and an old appmobi audio API that probably doesn't need to be there any more). There are still major platforms without web audio support (mainly IE, old Android browsers) so don't forget all these features need to have some reasonable fallback when running with HTML5 audio. My point is you are trying to make it sound easy to implement but it's not quite that straightforward. Particularly with #3 (extended looping), we actually still play music tracks with HTML5 audio routed through the web audio API due to its ability to stream which reduces latency and memory use, but it doesn't support anything other than looping the entire track as far as I am aware (and sadly on most browsers not even a seamless loop). It's not simple to just switch music to the web audio API, because we used to do that, and on some devices (particularly Android) it can take 30sec+ just to decode the entire audio file, then it has to hold the entire track in memory (30mb+ per track), and if you free it to try to save memory, you have to do the 30sec+ decode again next time you want to play it.
One day I'd love to make a clean break and rewrite the audio plugin to use Web Audio exclusively (with just HTML5 audio for music streaming) and add a bunch of new features, but I don't think it's a good idea to do that until browsers with web audio support have something like 95%+ share. Until then adding features to the audio plugin can be pretty awkward.