You are actually wrong imo. Cataclysm is not for padding here. It does damage to all and applies Doom. We say padding when you dps useless adds or adds what would die fast anyway! In council fights, there is no such thing as "padding"! It is like expecting mages to play arcane...
Okay, if you want to use that definition of padding then I will say "cheesing" the meters. And arcane doesn't have cleave, DS / GoServ does
The reason I say padding / cheesing the meters is this. You are not doing what you "should" be doing for the fight, of course this depends on your raids strategy. The strat that I see everyone doing is DPS one, while cleaving the other two, then dps the next one while cleaving, then dps the next one while cleaving, then in p2 single target burn ( with minor cleave if you can without losing ST ) and repeat. What you are doing is just going AOE and basically shit single target, because lets be honest, Cata + GoSyn's single target is quite crappy. It isn't pure dirt, but it is nothing compared to GoServ + DS right now.
So for Iron maidens. If you go cata / syn you are going to gain what 4-5k DPS overall, and that dps is going to be on the targets that don't really need the DPS when you are dpsing them. Yes, at some point they need the damage done, but not at the time you are doing it, the time you do DPS to a mob is more critical then the damage you actually do to it, which is what I think you are missing here. This is even more prominent in P2 where you want the single target damage that GoServ / DS gives you.
Trust me, I agree that Cata will give you better numbers in the end, and for farm w/e go ahead who cares. I do it on LFR cause LFR is a joke. In progression though you need the damage on the right mobs at the right time, and you need that extra single target damage that you get with GoServ + DS. The additional numbers you get isn't worth that loss of single target damage when you need it on a progression pull.
Of course, like I said, this depends on your raids strats, if your raid does something different where you don't care who goes on the boat first, or you just aoe down the 3 in p2 ( is this a thing ? ) then it is w/e.
I have not seen any Cataclysm hotkey. Am I blind? :O
It is under hotkeys, right side.