Important point: Raikou does not have to have the same strengths as Garchomp in order to be banned. Banning is case by case.
When Syb talked about how it's similar to Garchomp, he was only pointing at one quality they have in common: The ability to wipe out 3-4 or even more enemies once it's set up, and the set up being very difficult to stop.
I'd also like to underline the fact that "counters," whether they exist OR NOT, are far from the only thing to consider when thinking about a ban. Just like lack of counters does not mean "broken," the existance of counters does not mean "not-broken."
Kyogre has counters in OU. That doesn't mean it belongs in OU. We all understand, Raikou has a lot of reliable counters-- listing more does not really do anything for the argument. The problem with Raikou is different.
Also Umbarsc, be a little realistic-- even if you have a well-built team with 4 or so pokemon who can each handle raikou in some way or other, that doesn't mean they'll necessarily be able to stop the sweep throughout the battle).
I am pretty much on the fence about Raikou. Honestly, outside the ridiculous amount of support Abomasnow's auto-hail provides, Raikou is the only pokemon that really stands out to me as a suspect. That being said, I can easily understand (and agree with) the many arguments that "it's not broken."
-Gastrodon's problem isn't how good its defenses are. It's the fact it has crap support options, and does not hit hard enough with its neutral moves. In OU, Vaporeon, Tentacruel and Swampert are the top Support-Bulky Water pokes because they have wish, t-spikes/rapid spin, and stealth rock respectively. If Gastrodon had SR, I'd be all over it, but as of now Gastrodon can sit out there recovering all day and not accomplish much.