Blissey
HP: 255
ATK: 10
DEF: 10
SPC: 135 (over 75)
SPE: 55
Essentially a better Chansey. Uses the same set as Chansey (Soft boiled, BoltBeam, and T-Wave). Both don't get anything interesting in this meta sadly, but they more or less already have what they want.
Also, what about Kyurem and it's forms?
Kyurem
HP: 125
ATK: 130
DEF: 90
SPC: 130
SPE: 95
Rock Slide
Blizzard / Ice Beam
Hyper Beam / Slash
Mimic / Psychic
While Kyurem's movepool is just as bad as his BW1 movepool, he gets the two moves he needs. Kyurem has good bulk and nice mixed offenses. Blizzard is the main spamming move here (which is why Ice Beam is viable, because of PP issues). Rock Slide decimates any Ice-type that tries to resist Blizzard, and hits pokemon with high special in their weaker defense. Hyper Beam is pretty much standard on things with bad movepools. However, Slash crits like it's no bodies business. Mimic can potentially give you coverage, while Psychic can lower Special (and it's pretty much neutral). 95 is a decent enough base speed, although it is a bit underwhelming. His typing, unlike in Gen 5, is really good, giving him all the bonuses of being a Dragon without the weakness to Ice. The Ice-type makes him weak to Rock though.
Black Kyurem
HP: 125
ATK: 170
DEF: 100
SPC: 90
SPE: 95
Rock Slide
Blizzard / Ice Beam
Hyper Beam / Slash
Mimic
This is probably the worst Kyurem form due to the lower Special, although he is still better than most. He suffers from Dragonite syndrome, as he cannot use any STAB except for Blizzard which hits from his mediocre Special. Rock Slide and Hyper Beam/Slash are your best bet for attack. Mimic is the last slot because he has nothing to run there. Psychic is less useful on Black Kyurem because his special is too mediocre to abuse Special Drops.
White Kyurem
HP: 125
ATK: 120
DEF: 90
SPC: 170
SPE: 95
Rock Slide
Blizzard / Ice Beam
Hyper Beam / Slash
Psychic / Mimic
Meanwhile, this is probably the best Kyurem, since his Attack is only slightly lower than normal Kyurem, while having that huge 170 Special. Rock Slide is to hit other Ice-types (cough Regice cough) while Blizzard / Ice Beam is spamable STAB. Psychic is primary slash because 170 doesn't mind the lack of STAB and Special Drops could spell doom for your opponent.
Also, can we assume Legendary Pokemon keep their Signature Moves? Or are we strictly going with Gen 1 moves?