You're right, is the future, not the present. According to the
IPv6 Information Page there are a
ridiculous number of IPv6 enabled Web/FTP/Irc sites compared with IPv4 ones. Yes, that list is outdated but i'm sure that an updated one won't reflect an enormous growth of IPv6 sites.
IPSec, 'cool' IPv6 addresses and IPv6-over-IPv4 are nice things but in my opinion isn't 'critical' to implement IPv6 support on a program (irc, ftp, etc) now because only a 0.0x % of users will need/use it.
By the way, i've checked
this page of SmartFTP's knowledge base and according to it there're only six (
6) Public IPv6 FTP Servers ... are you really telling us that you stopped using FlashFXP for those six public servers?, c'mon ...