The main plot of Izayoi when he joined the No Names was to get back their name and flag and to beat the demon lord who got it,right? So season 1 ended not with that but defeating a rookie demon lord. (pest) SAO's plot was to trap players and for kirito to get them out and it happened and that was a perfect ending in the half of the show . So I think , Mondaiji Tachi hasn't fulfilled the "get our flag back" plot so likely, possibly there'd be a season 2.