Charge move damage is 20% higher with future sight.
It's ~12 uses of PC to get full bar charged up. both have a 10~11 second cycle time. That's ~60 base damage from quick attacks, and either 100 or 120 from charge move.
Ergo, base damage per cycle is 160 vs 180, and cycles about the same length. DPS with the new one would thus be something in the neighborhood of 12% better, all else being equal.