Tyranitar/Dragonite rating
I still don't see why Tyranitar and/or Dragonite hasn't got a 10/10 rating while a mon kike Machamp does. Machamp has much worse stats than both. It counters 3 raid bosses effectively. While Tyranitar counters pretty much all the birds, all the beasts except suicune (Raikou isn't really countered by Ttar)
Dragonite is THE best generalist in the game. But neither are 10/10
Answers
Machamp is the best answer to the best defender in the game (Blissey), and is also the best answer to the best Tier 4 raid (Tyranitar). For Lax, Lapras and Ttar, the next best option is far and away inferior.
I guess it's part to do with the game shifting away from gym meta to the raid meta- Machamp is actually the best for a few things, but neither Ttar or Dragonite are best for anything (though still very very good)
That is very true but for the 7 legendaries we have seen so far:
Articuno- Countered by Moltres and Flareon (exception: Iron Tail SE Tyranitar is right up there as the best), Dnite gets wrecked
Moltres- Countered by Golem Better, Ttar is OK, Dnite is not really good
Zapdos- Countered by Golem better, Ttar and Dragonite are OK
Entei- Countered by Golem/Vaporeon better, Ttar and Dragonite are Good
Raikou- Countered by Rhydon better, Dragonite is OK, Ttar is not so great
Suicune- Countered by Zap/Raikou/Exeggutor, Dragonite is very good, Ttar gets wrecked
Lugia-Ttar is the best here! Until it has hydro pump...
So...the coverage is good, but not spectacular. Ttar might deserve more credit as a 10 but I don't think Dragonite should be as far as raids are concerned. The only raid in which I have used a full dragonite team is Suicune and it consistently gives me 2 damage balls.
That said, if 10 pokemon gyms come back, then we can see Dnite/Ttar climb up to a 10 definitely.
I think due each month having a new raid boss raitings are impossible to do. In Europe rock and water are 10/10 this month due to entei. But when Suicune come they would fall at least 2p.
It also depends on battle style (dodge vs no dodge) and raid climate. If you have many players raiding a mewtwo a lvl 40 gengar with SC/SB is 10++++/10 while in a smaller city with 4-5 players on a mewtwo raid it is 1/10.
8-10 in raiting is impossible to differ and you can argue both ways.
Machamp rated as 10 may have to do with the way I hate when the game preselects T-Tar or Rhydon every time I'm fighting a Blissey/Snorlax in a gym. I don't understand why the game insists in giving me an inefficient and time consuming pokemon, when I have several machamp that can run through Blissey in a smooth way and short time (even when receiving super effective damage). Neither T-Tar nor dragonite can do that...
All the above points are good, but I'm pretty sure the real reason that Tyranitar isn't a 10 is because the ratings were all compiled before the gym rework. Tyranitar and Dragonite weren't 10s because their double weaknesses were real hindrances on defense. If all the ratings were updated today, I think Tyranitar would be a 10, Dragonite would still be a 9,and Machamp would be either an 8 or 9.