If clicking U-turn and having Stealth Rocks on the field is a lot of support, every single team in the game qualifies as having "a lot of support".
Please don't exaggerate arguments that were not made. There is absolutely no link between the first condition and the conclusion drawn in the above quote. Having to U-turn out a couple of times definitely qualifies as significant support because it implies that you'll have had to have needed something to switch into the powerful attackers just listed, which is not easy in the first place. "Little to no support" when we label for a broken Pokemon is generally in the ball-park of "bring out the Pokemon, and either i) OKHO (the Pokemon that is currently in) or outspeed and 2HKO (the majority of switch-ins) Pokemon with a relatively easily spammable attack, or ii) sweep a major portion of the opposing unless your opponent puts in a huge effort to stop it. Something that fits this description is something like Blaziken, where you 1) it had very little safe switch-ins, and 2) it could just do something like click Protect or Swords Dance and immediately begin some form of sweep. Tornadus-T does not do this without significant support.
The problem with that argument is the fact that, while you can force Tornadus-T out with a full-health bulky mon, you won't be anywhere near full health endgame. The problem I see with Tornadus-T that doesn't apply to something like Terrakion, which is similarly hard to switch in on, even more so, is that very few things that aren't scarfers outspeed Tornadus (Weavile and Jolteon are the only two I can think of), and requiring either a full health poke or a scarfer to force out Tornadus-T is not reliable, since pokes get worn down, and scarfers are scarfers (ie. can be set up on if they pick the wrong move, etc). Strong priority is of course good against Tornadus-T, but those moves aren't always safe to go for if the opponent has a set-up sweeper or powerful attacker that laughs in the face of a Banded Bullet Punch or LO Ice Shard (of which there are a good amount). Tornadus isn't Swift Swimmer or Excadrill broken, but the pressure it puts on an opponent for the amount of risk it takes to click either Hurricane or U-turn is unhealthy for the game, in my opinion. It's just a little too sustainable, a little too fast, and a little too strong to stay in this meta, at least while Drizzle's around.
The problem with this is that pretty much any B tier or above sweeper in OU can do this. Cleaning up late-game is almost a non-factor, since ANYTHING could happen between the start of the game and the endgame. Something like ScarfMence or Scarf Kyurem-B can sweep endgame, because you probably ended up weakening Skarmory or something like that to the point where you can easily break through it in the late-game, just like how you probably weakened Jirachi/Chansey/Rotom-W/Zapdos/whatever so Tornadus-T could break through it lategame.
Anyway, since people are moving to Keldeo, I'll jump straight to Jabba's post. Yes, I agree that Scarf Keldeo is much better in practice than on paper. I tried it for a bit and while I thought it was overrated, it was still an excellent set. I also agree that it DOES play like a Swift Swimmer in a lot of cases. However, what makes the difference, is that while Scarf Keldeo has the Speed to match many Swift Swimmers, it does not carry nearly the same kind of power that the Swift Swimmers were free to use, or the ability to switch attacks. Scarf Timid Keldeo has 357 Special Attack and 519 Speed. You could use Modest for more power, but you outspeed WAY less threats, including Salamence and Landorus. Kingdra, the most commonly used Swift Swimmer that spammed Hydro Pump like Scarf Keldeo, carries either Specs, which boosted its SpA to 475 and had a 538 Speed stat. Life Orb had the equivalent of 412 SpA, but it had the ability to switch attacks, which made it way more dangerous. Specs Kingdra's Hydro Pump was 33% more powerful than Scarf Keldeo's. If incorrect Sand Force Landorus-I was considered broken in round 1 and corrected Sand Force Landorus-I was not, it proves that 33% is way too much to draw a comparison (Incorrect Lando-I's attacks were 13% more powerful than corrected). In terms of Hydro Pumps, Ludicolo had the weakest, and with a Life Orb, it was still more powerful than Scarf Keldeo's Hydro Pump, with the freedom to change attacks. You could say Keldeo could run Specs to boost its power, but where's the Speed coming from? Swift Swimmers were broken because they had BOTH the power and speed, often with the freedom to change attacks, while Keldeo can only have one of them.