I feel that with only arsenic doing damage, you would have to increase the deck size by just a tad. Also, I would convert some of your death pends (3-4) into entropy pillars/pends because with pends alone I doubt you would have enough to supply cats all the time using their ability.
As morm said I think pande + cats is a bit of dead weight since your pandes have a good chance to kill off your cats rendering them useless. Now, upped pandemoniums would make this deck rock. Interesting to say the least.