Case in point:
In his opera Rigoletto, Giuseppe Verdi really goes to town showing off his prodigious melodic gift. Themes, lines, full-fledged melodies: he does not economize. He just throws them right and left, all original, all unique, never repeating. The brief intro to Act Two is a melodic jewel, and yet all it does is convey to the audience a bit of tension: Verdi just leaves it there, never developing it later.
I would call it melodic extravagance - if it weren't for the fact that the word extravagant always comes off as negative to some degree these days.
If I'm wrong, please say so. If I'm right, is there a better word for it?
What I'm trying to convey here is that Verdi was generous with his gift. As in, "Hey, you want more melodies? Here, take another dozen."
Melodic generosity comes to mind. The only problem is, it could easily be misinterpreted ... uh ... misconstrued.