Replacing Roost with Sub is pointless as most neutral attacks deal 30-40% - breaking sub, but easily healed up with Roost. Even haxChomp has some trouble when Subbing every once in a while, and he has Sand Veil.
Heatran is the only Steel type that this Scizor has problems with (edit: Steelix as well). I can simply switch to Latios if Staraptor haven't killed Heatran already. I considered Superpower but Bug Bite hits stronger most of the time (135 vs 120), trolls ChestoRestos & Subbers and has no side effect.
I think Scizor is the most solid member of this team, he's doing what he should and never fails at that. Maybe use Ttar or Gastrodon to laugh at Electric and Fire?