I mean, as far as Cloud's Finishing Touch goes, it's mostly a gimmick. Won't deal much more (if any more) damage than a good SSB or BSSB as it is, similar to how most BSSBs deal similar damage to SSBs. Wouldn't be too worried about power creep unless we start seeing multipliers that exceed 8.0x by a significant degree (10-12x multipliers would be stupid, for example)
These OSSBs become ridiculously strong when we find out that the damage cap break is an aura that affects other things, meaning SSBs like Shadow's or BSSBs like Vaan's can break the damage cap too. That would be scary.