This!
MP3 is an old almost obsolete format, yes it's has been the de-facto standard for music files since P2P Napster and Kazaa days but there are far better audio codecs that have been developed since then that are becoming as standard as MP3 like AAC (and hopefully OPUS)
Also PS3 didn't launch with DLNA support either and it took about half a year before it was finally put add (
version 1.80)
I'd rather have all the features that ARE available at launch or when I get my PS4 to work without issue rather than have a bunch of issues with a bunch of features
They can always add stuff later, and of course they will...