Q u o t e: Why?
It just makes things more complex and skillful to fight in arenas as you have more to watch for..
Now you cant run around in circles like a chicken with your head cut off and actually have to watch out for other things..
Of course this would mostly affect 1v1 games as 4v4 already has more than one person to watch out for.
wo not just have obstacles like spikes or flame throwers hooked into the floor...oh wait. they did that in WoW....sigh
regardless. monsters would serve as a good mobile obstacle. If blizz feels the need to put damaging obstacles into the arenas they will.
the only problem with obstacles that move is that they induce a variety of luck into the game. I personally hate luck when it comes to competition. There would be nothing more frustrating than knowing you lost because that monster decided to pop out RIGHT at THAT time, and attack YOU, despite the fact that your opponent was in the same area