Hi, I'm ImpureGinger, and I main support.
I play Bard pretty often, and whenever I get to the mid-late game, chimes become almost irrelevant to me, unless I have nothing else to do. My suggestion for an adjustment (if it's necessary, bard isn't particularly adept late game regardless, that's probably intentional) is to change his ult to have a passive that lessens its cooldown by a second each time Bard collects a chime. Alternatively, maybe once the player gets a certain amount of chimes? It's not a huge buff, but Bard is overly lackluster in the late game and the extra uptime on his ult would help, and make chimes more relevant late game.
Thanks for reading!