So I've only skimread through this, but I think it seems at first glance to be a sensible course of action to drop a bunch of pokemon.
Just in terms of looking at what needs to drop, I'd say Ferrothorn. Spikes support is nice, but it doesn't really give it an edge over Skarmory. In fact, by comparison, sp def Skarmory can stomach surprise hp fires from stuff like Latios, and has actually good recovery in roost.
252 SpA Life Orb Latios Hidden Power Fire vs. 252 HP / 252+ SpD Skarmory: 156-185 (46.7 - 55.3%) -- 15.2% chance to 2HKO after Leftovers recovery
252 SpA Life Orb Latios Hidden Power Fire vs. 252 HP / 168 SpD Ferrothorn: 265-312 (75.2 - 88.6%) -- guaranteed 2HKO after Leftovers recovery
My other gripe is that Ferrothorn can sort of be overwhelmed, and it doesn't fill a lot of the functions that you want it to. So, for example, it lacks a phasing move, so if it tries to switch in on Excadrill, then Exca can potentially SD up then hit it with an EQ. In terms of stuff you'd want it to resist, it isn't actually a very good Azumarill switch in, due to getting wrecked by Band Superpower, or BD + Knock Off. It isn't actually a great water resist due to it hating being burned by scald. T wave is a cool tech option no doubt, but that means it can only run one attacking move which makes it even more easily exploitable, due to either Gyro ball's low pp, or grass being resisted pretty easily. Last point, big breakers in Heracross, Volcanion, and Magma Storm Heatran can switch in on it, which are all more common than they used to be.
I'm not saying it's a bad pokemon, it is still usable, but it shouldn't be ranked above Skarmory.
I still hold fast in my belief that Lando-T and Sableye are deserving of S rank, and that the latter is banworthy, but clearly not very many people agree with me.