So that's a great example of Genesis not staying current.  ReddCoin is no longer mine-able having moved to its Proof of Stake phase.  AuroraCoin seems to have flopped as has LottoCoin.  So really the effective choice/value comes down to Lite/Doge/Feather/Black/Mega, with payout in Bit/Dark.  Personally I would like a larger effective choice than five.

And on the sysadmin work front, the real complexity jump is going from one to multiple, unless there are horrendous manual processes hidden behind the scenes.  Certainly the variability of daily payout time and prior comments here about a manual sign-off process would suggest that the current Genesis infrastructure may not be operationally scalable in the multi-coin dimension in quite that same way that Bittrex seems to be.  And in saying that I'm not trivializing the difference between exchange and mining operations, but I hope you take my point to some degree.  Some of the issues in supporting multiple coins are common to both.