As of now, the arena monthly rewarding system is silly. It is basically an upscaled version of arena daily rewards, which rewards arena ranks at the stroke of wherever your timezone resides. I'm not debating whether the daily rewarding system is good or bad, but that the monthly rewarding system should reward consistency within the month rather than a single event within the month.
I propose an arena scoring system, whereby the daily arena ranks are averaged against the number of days calculated, and the lowest arena scores for the month tallied to determine the monthly arena awardees. That way, players who are consistent in that month are fairly rewarded instead of players who merely got lucky on that one day the monthly rewards are awarded.
I believe this is a simple, yet efficient way to reward consistent play. Cheers.