Most sites that use NIS have multiple NIS servers. authconfig-gtk should recognize this and give a clear way to add multiple NIS servers. One cool feature may be to allow the user to enter one NIS server, then click "Find more servers". authconfig-gtk would then bind to the NIS server specified and add all of the servers in the ypservers map to the config.
Comma-separated lists of servers are recognized by authconfig. I'm doubtful about adding the necessary RPC code to authconfig itself to search for NIS servers at this time -- there are too many things beyond authconfig's control which could make this not work reliably. It's a useful idea, and there's even some autoprobing-via-DNS stuff in there, so I'm not going to reject this completely, but it's going to have to be deferred until I get more time to look at it.