This is a video i found, ignoring his play style and spec but just looking at whats going on in the arenas themselves
http://www.youtube.com/watch?v=NFPoIzSYRzM
Watch in high quality, but first impressions is that i am worried. The elevator one seems manic. Imagine that for a 5v5. Also in that same arena if iwant to get to someone and have to cross the fire while in stealth that could ruin everything (like it did for that guy) if its on a specific timer then i am sure there will be add-ons sooner rather than later for it.
The first arena seems interesting. A large platform thats to high to jump up to (i think) with a huge pillar of water that comes down every so often.
The thing that confuses me is that i watched the 3v3 arena finals in Spain and the Blizz guy who was there commenting on the matches said they were most happy with Ruins of Lordaeron where there was a good LoS tactic to be played but not so much going on like blades edge. Seems like these are both much more complex than RoL....