One thing that bugs me, is on really long note block songs, you have to follow it down to hear the whole thing. Now, I don't even know if this is possible, a mod to make the note block sound stay at the button/lever you press, rather than fading off, would be amazing. Not getting my hopes up, seems like a stretch bump cause it looks like it's getting lost EDIT by Moderator: merged posts, please use the edit button instead of double posting.
Not necessarily. All the server would have to do is tell clients that the notes in question are coming from somewhere closer than they actually are. (Not sure how easy this is without sending packets manually).