Those are basically two suggestions here, so I'll adress them individually:

1) I dont really understand what you mean by saying you feel its "lazy" for them to give us music as rewards for quest. I very much like that - and I dont think its like we're getting the music instead of something? So its not "lazy" its "extra" - we still got our minion from the last mainquest and on top of that some music! Seems fair to me, music hasnt replaced (unique) quest-rewards, it has been added. So please, keep doing that!

2) Playing music on mounts has been suggested multiple times - apparently its not to easy to implement that though - some complicated audio-code again. On top of that: Personally, I like certain mounts because of their specific music... so... while I'm not really "against" that suggestion, the specific-mount music can also be an extra intencive to farm/use that mount. And you can always mute the game and play some other music, so I dont feel that its to needed - aka: if its complicated and takes away time that could be used elsewhere... use it elsewhere