I wonder if they'll balance Overflow SBs by just increasing the DEF/RES of enemies to the point that you aren't ever going that far over cap anyway.
Damage formula is already non-linear, so I don't think it would be that hard to make this kind of tweak. The video we saw of course each hit was doing like 90k, but this wasn't on a current endgame boss, so it had horrible stats, on a reasonable boss the damage probably would have been much lower.
In parallel with this, they could start releasing more multi-hit SBs that have very high number of hits (hell, even 20+) but with low multipliers. This would mean it's going to be really really hard to get these SBs to break the damage cap, so you would never benefit from using an overflow on it, but at the same time you would be doing comparable damage to someone who is using an overflow (because they are doing fewer hits, but more damage each hit).
One thing that doesn't change though, is that bosses are going to get stronger.
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