Here is my opinion on the current slate.
Latios A+ > S: Latios is a good Pokemon, sure. But it just isn't an S Pokemon. I can leave a match, and say, win or loss, that the S Pokemon got a kill or was supportive. Latios I really can't. Sucker Punch sends it Mars and back, with Knock Off and Darkspam as common as ever, I don't think it is Latios time to shine.
Kyurem-B A > A-, Mega Gyarados A > A-,
and Mega Metagross A+ > A-: I lumped these three together, one, to save time, and two, in my eyes are in similar situations. All three are strong, physical attackers that can wreck havoc. However, they each have their issues. Kyurem is slow and doesn't have access to reliable, physical Ice-STAB. Gyarados eats up a Mega slot and while is good, just isn't WOW THAT'S GOOD, and MegaGross eats up a Mega slot, has a bad accuracy on it's STABs, and has weaknesses to Dark and Ground. I could see MegaGross and Gyarados dropping, but Kyurem's undeniable power should keep it in A+.
Latios A+ > S: Latios is a good Pokemon, sure. But it just isn't an S Pokemon. I can leave a match, and say, win or loss, that the S Pokemon got a kill or was supportive. Latios I really can't. Sucker Punch sends it Mars and back, with Knock Off and Darkspam as common as ever, I don't think it is Latios time to shine.
Kyurem-B A > A-, Mega Gyarados A > A-,
and Mega Metagross A+ > A-: I lumped these three together, one, to save time, and two, in my eyes are in similar situations. All three are strong, physical attackers that can wreck havoc. However, they each have their issues. Kyurem is slow and doesn't have access to reliable, physical Ice-STAB. Gyarados eats up a Mega slot and while is good, just isn't WOW THAT'S GOOD, and MegaGross eats up a Mega slot, has a bad accuracy on it's STABs, and has weaknesses to Dark and Ground. I could see MegaGross and Gyarados dropping, but Kyurem's undeniable power should keep it in A+.