I still would've been satisfied if S3 was the series finale
Minus the couple of loose ends still lurking about in the show like White Rose keeping Elliott alive because of his potential and Dom now being part of the dark army, I think it ended relatively well and I would've been satisfied with the ambiguous ending that S3 left us with.
Regardless I'm still excited for S4, I just hope it ends on a high note for Elliott. I was bummed when I heard S4 was going to be the last season, but it seems one more season is all they need to wrap everything up.