Spreading the trading thin on multiple exchanges is not good for a small volume coin.  Additionally, since the coin is so young and things change from time to time, exchanges look down on having to go offline to redo mandatory wallets.  The thing that has been talked about is after Masternodes (Sanctuaries) go online in late December, the Dev (well, the DAO at that point) will look at adding more exchanges.  Hopefully by then, volume/pricing will be sufficient to maintain a healthy trade on more than one exchange.  Right now with the price hovering at 11 to 13 satoshi it takes a lot of volume to make it worth an exchange's time.  We are getting by on C-Cex since they consider us a charity style coin and not quite subject to their normal rules.  The hope is that Masternodes will be the jump start to move this coin forward to the point where it becomes reasonable to be on more than one exchange.