Okay, in all honesty, I rarely if ever post on the forums here, and I've been on several very long hiatuses (I popped in about a week ago to see Talonflame banned in Mono OU and that shocked me, let that sink in about how long I've been gone, but that's old news on this thread and I am not going to drag that up again, I've already subbed Infernape in where Talon used to be and moved on, whether I agree with it or not).
Now it's a bit late and I'm only awake because there's something scurrying around in my walls and keeping me up, but bear with me please.
I don't really ladder well, I'll be the first to admit. I LOVE battling, I LOVE testing teams. But for the love of Arceus I just can't ever get higher than 1500 no matter the ladder. It's not that I'm clueless as to how to use good Pokemon well, it's not that I don't learn from my defeats. It's the fact that laddering just gets to me, I just can't handle the pressure well. I can feel my blood pressure rising on turn one of a Ranked Battle, so I can't handle more than a few fights a day. But day in and day out I love to run calcs, I love to do unranked battles with friends. I'm just giving people a bit of an idea of how I work here, that no, I am not the best ladderer, but I do love Pokemon, I love Competitive Pokemon, and one of my favorite Metas is Monotype OU.
Swift Swim+Drizzle, from what I've seen and from all the evidence people keep giving, is just not fair, and not healthy, plain and simple. I may not be a top player but it doesn't take a genius to figure out that this combination is unhealthy for this environment. Banning Damp Rock won't be enough, all most offensive Swift Swim users need is the 4 turns they get on a swap to tear open a hole in the enemy's team. Heck, we've even seen evidence of how just Rain Dance+Swift Swim can lead to hilarious Sweeps against a Neutral team.
Personally, my favorite Mono to run is Fire, and let me tell you I just gave up on winning Weather Wars against Rain after Talonflame was banned, he was my main means of stopping Politoed after luring him out when the rain was over (And even that had to work twice in a row, which still tended to result in me losing). I even gave up using MCY and went for X, which had actually helped me significantly against a significant amount of teams (Less people expected it, and people running Sap Sipper Azumarill seemed shocked by the even less expected Thunderpunch over Outrage/Dragon Claw.). Volcarona's Giga Drain is nice but unless it's at a minimal of +3 Speed, it's getting vastly outsped by any Swift Swim user. And if the opponent has Rocks up? Arceus save my soul was I boned in the rain, even Sassy+Vest Torkoal with 252HP can't take a STAB Hydro Pump in those conditions (I have my reasons for the Vest over Lefties, namely that Torkoal needs to SURVIVE a hit to get those dreaded Rocks off the field, and the vest has let it tank unboosted Rotom-W Hydro Pumps before).
Anyways, sorry if I'm rambling a bit but please, PLEASE don't let the only nerf to this powerful combination be "Ban Damp Rock". 4 turns is all a Drizzle+Swift Swim team needs to absolutely demolish just about any Mono Fire team it comes up against, you can only sacrifice so many teammates to get Megazard Y out, and Megazard Y can only take so many hits. Even with Roost in play (Roost on the turn they swap to Politoed, swap back out, lather, rinse, repeat), it tends to make the battles last too long for most people's liking. Plus, you don't WANT to send out Megazard Y against most of these SS Pokemon if you can help it (bar Ludicolo), which tends to end with a teammate being sacrificed to preserve Charizard.
252+ SpA Kingdra Draco Meteor vs. 4 HP / 0 SpD Mega Charizard Y: 168-198 (56.3 - 66.4%) -- guaranteed 2HKO
That's too much damage for Megazard to keep Roosting away, eventually it'll get whittled down enough. And a lot of Kingdra I've seen seem to go for Specs or a Life Orb, if it has that up I doubt even 252 HP would save the poor lizard. This is of course an offensive Megazard Y as opposed to a Defensive variant (if anyone even runs that), and I used the standard OU Kingdra on the calculator, I'm not 100% on what the Mono OU Standard is.
252+ SpA Choice Specs Kingdra Draco Meteor vs. 252 HP / 252+ SpD Mega Charizard Y: 184-217 (51.1 - 60.2%) -- guaranteed 2HKO
Yeah, look at that, Kingdra is entirely capable of, with the right item, over the period of a match, whittling down just about any Megazard Y set as it vainly tries to swap in and out to keep you from obliterating it's team with Rain-boosted STAB and Speed.
I shouldn't even have to go into why swapping into Kabutops is a bad idea for Megazard Y.
It seems to be able to handle Ludicolo just fine granted you gave it Roost, but that really turns into what feels like an Endless Battle of swapping your Weather Setters in and out repeatedly, healing as you go along. The only way I could see this battle ever going in the Fire user's favor is if the opponent ISN'T using Kingdra or Kabutops, or if the Fire user is packing Ninetales as well as Megazard Y, but even that's iffy at best, as well as being redundant and taking up precious team slots just for the times you face a Drizzle+SS user.
I've been at this for a while and I feel ready to pass out. I know my examples are probably redundant at this point, and that people are probably going to disagree with me on the grounds that I'm not a top ladderer or that I'm not always on Mono OU, but please, please consider what I have to say here. From everything I've seen and the reasons I've given, logically speaking Drizzle+Swift Swim needs to be stopped for the very reasons Talonflame was supposedly banned: It gives one Type a nearly unstoppable advantage over another to the point that Fire cannot feasibly beat Water if they run this set, without having to run otherwise bad or obscure Pokemon or sets.
I've never run Mono Rock or Ground myself, so I'm not going to touch on those. But I'm going to assume that, unless Rock's Weather Setter is AV T-tar, it's in the same boat as MCY, and the same goes for Hippowdon.