Having fought off and on for almost two decades in arenas I can tell you time based powers and wormholes/blackhole based powers are usually never allowed because the abuse potential is high. Firearms are frowned upon by some people because they don't understand how they are used or how to combat them. I love firearms in the arena.

I think your mecha cat is a good character that few people here can handle. Not because they aren't good fighters but because most fights here are kept in a specfic box due to a lack of experience against diverse opponents. 

People bitched and moaned against my gunfighter-esque character because he didn't fit into their box of knowledge. It happens.