Quote:

Personally, the above 7#9#11 chord would most likely sound ok if A7#9 was played and the #11 omitted. My experience is that many of these extended chords have the characteristic extension note(s) in the melody and they are, therefore, not needed in the harmony.





If you're thinking only in terms of functional harmony yes, but if you want to use chords for 'colour' or in non-functional 'modern' settings what the extended chords give you (theoretically anyway) is a greater chance of hearing more semitones in the voicing, the 5th against the #11 or b13,.. the 4th against the b5th ..etc.
For me BIAB has a tendency not to play back too many of these 'clashes' either by accident or design.
I can understand however that for the purposes of reproducing standard song-forms in the style of a certain era, there won't be too many people unhappy about that.

Regards

Alan