While I consciously know that 6 Support is overkill, I still run into the problem that I experience injuries. Because I experience injuries, I'm forced to run parties that are not what I had planned, or not run the party at all until the hero(es) heals. Some of the heroes that are injured carry the Support items. If I were down to a party of 5 Support as a baseline, and say Louca was injured, I'd be down to 2 Support. I don't like my odds with 2 Support, but I can probably get away with 3.
Having more Support gives me more flexibility with party configurations. If I ever get a 100% revive team, I will shift it down to 5 Support.