Season 3 should be finale, for me as a audience I don't want to see the same thing , Joe stalking new woman every new season . Also he was a serial killer who kills people beacuse he thinks that he was doing right and by doing so I was just saving her love interest of all season , upto season 2 it's fine(as a stroy ) . I don't think there is need of S4 ,makers are destroying what they created till S2. I think Joe can never love any woman , he can only love stalking , killing, planning of running.
But , one that in which S3 has good point is that , they shows perfectly what they want to show. We should always be happy with what we have, we must control ours feelings.