ntp pool command
For future ntp (FreeBSD 10.2+ ntpd 4.2.8p3) usage would it be possible for the web interface to support the pool command (http://doc.ntp.org/4.2.6/manyopt.html#pool)?
Setting multiple servers you run the risk of them not being valid time sources. This is partially mitigated if you're using hosts from the ntp.org's pool project however all to this would go away if you use the pool command.
With ntpd's pool the client's maxclock will be used to set the number of possible peers and bad peers will be rotated out as needed with a since pool line in ntp.conf (https://www.freebsd.org/cgi/man.cgi?query=ntp.conf&sektion=5).