i wouldn't say any more than the seventh season only because i love Alias, but all the chracters would be getting older and looking it. you would have Sloane extremely old, Irina, the same, and Jack getting complete white hair. Syd looking a bit like her mother on the show (irina does rite now) and its much better to see thm look young and not like old agents like Dixon or something, and then Marshalls son would be like 3 or 4 instaead of 9 or something lame like that. you'd have to get a completely new cast.