Note block with redstone on top of it won't play

Intended. There must be air above the note block.

Why?

That's somewhat counterintuitive, with all the other things you can sling redstone dust over and have it work, but if that's the way it is then I'll go with it... But Redstone Wire appears so 'lightweight' in the game that maybe it should be treated as air in the case of a note block (IF !(air || redstone_dust) is on top of note_block THEN don't play sound). But I guess in the spirit of the game, the Note Block probably vibrates pretty badly when playing a note and all of the redstone dust on top of it would just fall off... Either way, I still think it would be easier and more compact if I could line up several Note Blocks and put redstone dust over the tops of all of them and have them play a chord when the dust is energized.

I agree that there should be some exceptions, such as with torches, but it does seem somewhat unreasonable.

That's a very annoying "feature". +1 for not WAI

For now.

I agree this should be removed. All it does is annoy.