Yah it sucks. Especially when you pay 50 crystals to snipe someone but get the message "Error: Your team is already engaged in an arena battle." because someone is sniping you.
I think a live arena ladder would do the game a lot of good. But lowering the rewards a bit but making it the highest rank reached over 24 hrs might be a good stopgap. It's not fair that some are on much more competitive laddes/payout times than others.