Glass Cannon Team

You lack a specific blue counter/coverage, which is the most common color rn. Other than that as long as they all have reposition and etc, I dont see any reason why it wouldnt work

thats not a bad team, but I would have to say that having a dagger and bow user together on the same team could be counter productive in certain situations where you would want a green unit instead. If you have Brave Bow+, Darting Blow and Desperation on B.Cordelia then I would say stick with her, but if not, then keep Kagero until you get what you need with B.Cordelia. And then replace the odd one out with a green unit like Nino, Hector, Minerva, or any other potentially good greens you have.

(Its a shame you don't have Bridal Lyn on that team, she does wonders against all those asshole Takumi, Hector, Ike, Ryoma, Xander, Camus and Dragons that counters all ranges and the Vantage they inherit... I got Bridal Lyn on one of my 3 accounts and she is AMAZING in arena to kill off a unit without taking damage, essentially giving you a real nice advantage in numbers.)

You won't get a high arena score due to you using lots of ranged units. Vantage hector could be a threat