Salamence for a lum berry because he can set up on and OHKO rotom-w, and he can also set up on blissey, zapdos, chansey, the list goes on. pretty much any wall, and stops confusion from outrage. Lefties rnt too good on mence, not as useful, and he doesn't need to stay in long to wreck the opponent.
U dont really need a magnezone, cos only noobs use magnet rise. u could c an air balloon one, but y dont u just hit it with fire blast? yeah, just get rid of the balloon and ur fine, ohkoing it with a ground move. gliscor counters it anyway. ur obviously not playing it rite.
with scor, if its a poke that u think has hydro pump or ice move, switch instantly to metagross. unstabed surf is no problem cos it normally fails to 2hko. the reason hp ice might ohko with SR is because he still hasn't been poisoned yet, or its a crit, or its from a specsed poke.
Ferro isn't too useful on this team, cos you counter everything he does anyway, and u already have enough bulky mons.
so rotom-w counters u? yeah, hes a beast ;0 I use him. super annoying, but as i said earlier, salamence survives a will o wisp cos of lum, and gets a dd, then ohko back with outrage. will o wisp can even miss, so u save ur lum.
Another check to rotom-w is Ferrothorn (only if it doesn't run hp fire) or blissey. she can heal off any burns and pass wishes 2 ur team, but if u use it, u have 3 weak to fighting