These give you .87 more Damage Per Second (DPS) than the Warrior's Axe, but if you're a WAR/NIN, it's hard to top the +2 STR and +2 DEX bonus from dual wielding the Warrior's. Unless you're getting the +1 Mythril Axes (great if you have the cash), I'd recommend keeping your Warrior's Axes and waiting for the Combat Caster's Axe and/or the Razor Axe. Here's a quick comparison of your choices:
I think you're a bit mistaken on DPS there. Keep in mind there is no delay reduction with Dual Wield I. DPS when dual wielding is determined by adding the DMG of the 2 weapons together, then dividing by the sum of the delays divided by 60. For example, with 2 Warrior's Axes, it would be 50/(552/60). Correct DPS for the options you listed: