Welcome to Arena challenge #1!
I don't mind you've copied my design, it's a pretty solid design I feel. Although hopefully someone will come up with a better design for a reacher than what I've used.
My biggest beef with your mirror design is that it moves the arm really close to the wall, and that it has weak anti shove protection. It can easily be beaten by a simple pusher: http://FantasticContraption.com/?designId=943034
*Watches how everyone rush in to beat the wall pusher...
I don't want anyone to beat the wall pusher. I believe air combat is where it's at. But in order to be a good contender for arena #1 champ your design has to be immune to wall shove tactics.
You can read my notes on anti wall pushers here: http://fantasticcontraption.com/forum/viewtopic.php?f=5&t=81&st=0&sk=t&sd=a&start=100#p5999
Once your design is wall shove immune, it has to brace itself for air warfare! So far we've had a number of air warfare tactics used in this thread, you can go back and have a look (though most of the thread is wall pushers. The air stuff first appears on page 6 I believe, and is scarce).
The basic methods we've seen are:
1) Beat the other guy to the ball (like your design does)
2) Use of force to knock back the opponents arm away from the ball
3) Distrupt the enemy's mechanism by means of tossing ball/stuff at it (I don't care much for this type because it's a one trick pony and often can not even win vs thin air, or be very easy to beat by anything, but it can beat a single contraption if you care about that)
Seeing these tactics, if you can build a contraption that's better against these things and beat my contraption then I consider it advancement. You can modify my idea for that or make your own, but don't just beat my contraption. Make your contraption as hard to beat as you can.