As long a with jobs, playing Y Class dose not = xxx job only, I think the system will ada a lot to the game.

I think if jobs are more rolls that buff your class, and focus/limit its ability's but make it exceptional at that job in the party, then it will make for a very interesting Change.
An each job buffs each class in a slightly different way. ( I think they should not be accessable to all class, they would have to work for the class so some would be more limited then others.)

If on the other hand you just get to change only from a class to a specific job (so more more like you ranked up glad into uber tank), then well meh, yeah roll on FFXI job system plz.