Actually no…
Looking over this more critically, vertical slash is actually worse then bad… It’s terri-bad… (Terrible and bad)
Think about it… It’s max base dmg is 635, so if it only adds the missing DEF as damage plus 100 damage per debuff.
On current end dame conteint it’s only going to be hitting 1335 DMG (with just skull swing debuff.)
That’s Just barely stronger then cross slash and A LOT weaker then Moulinet.
And even when we get to a point where enemies have 1000 DEF that’s only 1735, which is still not much stronger then Cross Slash and still weaker then Moulinet.
And at the point where enemies start to have 1500 DEF or even 2000 DEF, that’s going to be 2735, which is finally just barely stronger then Moulinet, but weaker then the rank 6-7 skills.
And at a point where enemies would have 2k DEF the rank 6-7 skills would likely have been long since out classed by stronger ranks anyways…
That makes it REALLY bad, because it scales poorly with a minuscule stat.
You COULD get it double dmg by using lunge first, but you would still achieve higher DPS using just about anything else.