is that legend mihawk worth benching regular raid mihawk?
Enh... I'm going to disagree. I have both in Japan in really good shape: max skill, 5 ability heal raid Mihawk, and 5 heal, 5 unlock, 4 cooldown, 4 silence Legend Mihawk. Thanks, 1/2 stamina event!
Against big QCK baddies, it's likely you'll still be bringing in the DEX for the raw damage. Even against PSY, raid and legend usually end up being interchangeable, and dual max-skilled raid captains usually lead to a faster clear time.
The first issue is that the raid special works with most any crew (even non-slashers), but the legendary special requires very specific burst slasher crews to prop it up. To compete with the pure percentage cut, you'll need a solid round without missed perfects, plus matching orbs, a slasher-type booster, and Doffy. The slasher-type booster shouldn't be facing reduced damage, which means having both Koza and Mr. 1 on hand, or at least Prisoner Daz Bones, at maxed levels because of their average attack stats. If you're fighting PSY and there's no debuff shield, a slasher delay special (such as Mr. 3's) + Whitey Bay is also viable.
Then the boss gets a round to potentially do something, after your burst and before the special. If that "something" is locking your captains, and you don't have the ability orbs or specials to clear that, you're screwed. If you tick the boss's HP under 20% in the burst and trigger a preemptive counterattack, you're screwed, unless you're going to negate the damage somehow. If it's a heal instead of a kill (i.e. Ivankov), you'd better hope you have the damage potential to burst a second time.
In most situations where you are creeping a boss up to a problematic HP trigger boundary, then boosting to secure the finish, raid Mihawk's special is a viable fire-and-forget option, while legendary Mihawk's requires a perfectly-metered burst that drops the bosses HP in an exact spot, while still providing enough damage to make the special worthwhile. With max level units and predictable orb setups, this can be done reliably, but with any variance in the mix, I find it very, very easy to screw things up.
The legendary special also currently requires a really, really long stall, which usually means being slotted for healing and cooldowns. It's a little easier with the coffin boat maxed, but sometimes you need to bring the Thousand Sunny's cannon to clear trash mobs. If Legend Mihawk's cooldown gets to a 17 or less, he'd probably be considered better overall, but his special manuals haven't landed yet. Even when they do, as Whitebeard owners know, leveling a legendary special is a specific sort of hell.
In short, Legend Mihawk's really designed for high-tier setups used by players with a lot of max level, max special units, often looking to farm the colosseum. If you just need a slasher boost captain, raid and legendary are practically interchangeable in most circumstances.
Another point worth noting is that combo defense shields severely reduce the viability of
both units' specials. They are both considered single hit attacks, and unless you use a multi-hit special such as Nightmare Luffy's to drop the shield, you'll do 1 damage instead.
To bounce to some other topics, first, why are Brook dupes as rare as GP Usopp manuals on my Global account? Second, Parage Shot Sanji may be one of the best New Year's units next to Kimono Robin. He has excellent stats for a 10 cost unit, he's a 2x captain, and his skill's not bad either, making him pretty great for low-cost ranking. That, and he looks cool.
He might not be high-end, but I think it breaks the trend of nigh-useless Sanji units. Also got to see the newest Sanji's special in the Sugofest preview stage. It looks really cool. Cautiously optimistic that he'll break the trend even further, and have a solid effect, such as a 1-round boost for Toughness type.