Scizor can just do too much with one set to not make him a top tier Pokemon.
With a simple CB set, you get a scout, revenge killer, end-game cleaner, and trapper. He's got the bulk to take some shots and the typing to go with it. Any team can use him barring full-stall and that is the key.
Even with our new candle menace, Scizor can always U-Turn or throw down a Pursuit on the switch for big damage on top of Stealth Rock. Remember, if Scizor gets trapped and KO'd or set up upon, Shanderaa can be revenged with your own Shanderaa and a scarf. Unless Scizor is trapped on Super Power, any move will deal good damage or let Scizor switch.
I'm not too concerned, Scizor is the perfect mix of moves, typing, stats and ability to not be a top tier threat.