Your argument isn't really new, 7-8 pokemon aren't really important enough, I believe, to ban a move. Yanmega, Weavile, Togekiss, Salamence, Gyarados, and Zapdos show that Stealth Rock doesn't just eliminate pokes from contention.
The Pokemon you listed above are powerful enough to be OU regardless of Stealth Rock. Weavile is a great revenge killer, Zapdos can be a PP Stalling Wall and a Special Sweeeper; Salamence has immense attacking stats with high BP special moves to use; Togekiss is amazingly effective at paraflinching the opponent. Just because some SR weak Pokemon are still effective doesn't mean that other SR weak Pokemon aren't effected worse. All but Yanmega and Weavile are bulky, and Togekiss/Salamence/Zapdos get an instant recovery move. Gyarados has Dragon Dance to boost his stats with. I didn't mention these pokemon as being significantly hampered by SR, I just mentioned the BL ones that are.
If Stealth Rock was removed, however, it wouldn't be too much of a problem since each of them has solid counters (with exception of Salamence), and Blissey/Empoleon can take Specsmence, while all physical versions are countered by what one would use to counter an SD Chomp most of the time.
And to be honest, I think it's pretty neat that SR counters that Bellyzard set, and Rapid Spin is a 100% counter, it removes Stealth Rock. It isn't as easily dealt with as spikes, you gotta think a little bit. You spin, are they just going to send out their Steatlh Rocker to set up again? Tada, send in something that can mess with it.
Please leave the prediction out of theorymoning because it isn't limited to one side. Both battlers can predict; what if I sent in a Ghost Pokemon? Then your Rapid Spin attempt would fail.
If you don't have something that's a threat to Bronzong, Skarmory, or Forretress, you really aren't building a team too well anyways. And those are the 3 that stick around for a while. In a metagame full of suicide pokes that specialize in just setting up SR and dying an attack or two later like FS Azelf, Aerodactyl, and Deoxys, the concept of "kill the SR-user then spin" is not that crazy. Yes, many pokemon are capable of using Stealth Rock, but no one's really going to try using it on Garchomp or Metagross. They do other things too well. Heck, I don't even think "a lot of pokemon learn it" is a very good point to support anyways.
Not only defensive Steels use Stealth Rock. Hippowodon, Gliscor, and even Heatran are other common users of Stealth Rock. Even some Blisseys (albeit poorly played ones) can set up Stealth Rock. True, many Pokemon who learn Stealth Rock aren't the normal users of it. However, novelty sets, if they surprise the opponent, can be sucessful in their mission (to set up SR). And Skarmory and Forretress are not hard to deal with- anything with a special fire attack, even a Fire Blast Machamp, can get rid of these on their switch-in. Bronzong is the problem. But I personally haven't made a competitive team without a fire move, so I never see Bronzong as a problem. Especially since it has no recovery.
The amount of possible SR users just means that there is a higher chance that it occupies a moveslot on the opponents team. I didn't mean it with that intention. Unlike with Spikes or Toxic Spikes, if you need a Pokemon that can use SR, you have many to choose from. How doesn't this help the argument for Stealth Rock?
Spin and Wish Support, that's what you need.