Can't really comment or provide a mifune lineup as I don't have him or haven't seen a lineup with him. But I can say that root of warrior comp can be extremely strong but risky.If you don't have the BP to back it you'll get *n up pretty fast. You'll also want to have pretty good refines to be faster than your opponents. I suggest running someone who can shield your team or provide healing for your 4th person as MB can only buff 3. If you have the power to do so, I would run a full swordsman team especially since mifune can buff 9 by 30%. The best way to find out is to test it honestly.

There isn't anyone currently who provides a shield for swordsm*one or anyone who does it for light and earth ninjas. Mabui does give a shield to light users though and also gives chakra so you can fire off mystery's making you much more dangerous. The only thing is that you'll be lacking combos running Mabui, PB, Midnight, and Mifune. But you c*ways trigger a 10 hit with lights chase and PB's chase combined so that's a plus. Like Mayuri said, there is Cee if you have him. Gets rid off buffs/blinds, provides 20% res/def to light, and gives chakra. All this really comes down to your BP, the hits you can take and preference.