Welcome to Smogon! Take a moment to read the Introduction to Smogon for a run-down on everything Smogon, and make sure you take some time to read the global rules.
The Problem is actually when someone's using a slower Pokemon like Slowbro your strategy is quite ruined...
And certainly against Pokemon that won't OHKO you, Focus Sash becomes useless
You said you wouldn't mention legendaries here, but I think Registeel and Regirock aren't bad physical walls aswell, so a little note would be nice. Especially Registeel can wall CB Tyranitar, if not switched in an earthquake and earthquakes aren't as difficult to predict. Regirock in sandstorm...
Why does Steelix lose its Explosion?
Snorlax has Crunch now instead of Shadow Ball, which is slightly better than Shadow Ball was, because of the Def Drop Chance
Dynamic Punch/Cross Chop/Close Combat, Stone Edge, Eartquake/Fire Punch/Thunderpunch/Ice Punch, Eartquake/Fire Punch/Thunderpunch/Ice Punch
some stuff like that i guess, @CB or Flame Orb
EDIT: for EVs I'm not really sure, but I'd max Atk and HP
If you have doubts in my skills, you can battle me if you wish ;)
I'm on pretty often, so I don't think there'll be problems to handle the matches.
But anyway, I didn't completely understand the rules. Is this just a simple OU tourney with 6 pokemon and 3 pokemon to change during the tourney...