I'm an FCS man too, through and through, but this does make a lot of sense. From a consumer standpoint it would make ordering a board a little easier. Not having to decide between fin systems or figure out which fins would feel like its opposite.
Firewire is big enough to take this step out into the darkness with confidence and see where it leads. It will be interesting to see if any other brands follow. If the majority of FCS fans are in AUS I could see Hayden doing the same thing, but for FCS.
Also, one would think Slater would have a hard time with this... but most of his boards (if not all of them) are customs anyways (and he is a majority owner) so I doubt this change will have any effect on him whatsoever. It is very interesting though.