Vector movement

Just ran a FT demo at local game shop, and was rather delighted with 
response--even pulled some people away from the Magic games that had 
overrun the place.  But am concerned--major 'selling' point for the 
game is simplicity.  As I put it, if I can teach it to an 8-year old at 
2 AM on 2nd day of a Con, I can teach it to anyone.  But movement 
system took a wee bit to explain to a few people.  How much additional 
complication does the vector system add to the game?  I know I try to 
think about moving a ship in three directions at one time and my eyes 
glaze over.  How much does the vector system detract from the 
incredibly simple nature of the FT rules?

John