Too bad Auron isn't good in range attack, huh?

Dante's Sparda is actually as big as Auron's sword, if not bigger. Dante isn't shabby in sword fight either, so there is no guarantee that Auron would win easily even if they are to go into a melee duel due to Dante's ablity in evasion.

Also, Dante can change to Ifrit gaunlet and have an advantage in really close ranged fight. With weapons, you will have to swing it and whatnot, but with his fire enchanted gaunlets he can just punch and kick away.

About Bangle of Time, Dante can use it when he has his Devil Gauge, but my argument is he wouldn't use it unless it is for stopping Auron to execute his devastating attack. The fact that it only needs 3 symbols to trigger Bangle of Time, Dante will be able to use it when Auron decides to use his overdrive. (Like I've mentioned, it is easy to fill devil gauge.)