Just got done playing through most of the Last Update:
Difficulty does not influence Rewards in Arena Battles, so there is no Point in changing to a higher Difficulty at all, besides the Challenge, right? (not that Im complaining, mind you. I think that's good)
I would look into an automatic-Turn-end-Feature if possible. This has been bugging me in the normal Vanguard Battles, but after the Turn has ended, you have to select a squad again and then manually end Turns. with only one Squad on the Field, that was really getting on my nerves, and is removing every incentive for Replaying the Arenas
When Squads are leveling up from the new Academy XP System, The Squad Numbers, not Names are mentioned in the Message. The Names would probably be better and more informative for most Players.
the Chest in the Cahllenge Battle cant be opened, if you dont have a Lockpicking Thief with you. Is that intentional? And if so, why have it there at all?
finally: I might have encountered a Bug. The cavalry Squad from bristols areana fight, second phase, just rode straight through the barrier at the chockepoint between first and second arena area and attacked me. Afterwards standing inside the Barrier, i could select and destroy it, then destroy the Barrier. So nothing gamebreaking, but I'm pretty sure Barriers arent accessible to enemy Squads either?