Benimaru Team: Definately Shing0+, he's been toned down ever since his 98 incarnation, where he was a monster.
Korean Team: No weak link, but if you're talking about weakest, it's Kim. "Gee Oro! What are you saying, Kim is soooo good!" Yeah, but after Chang gained the armour mood crap, Jhun in armour mode, and the cheapness of a good Choi, Kim pales in comparison.
K team: Initially it's going to Maxima, he lack enough mind games to make him very good, he has low B combos, but they are lacking. But I guess in 2k with his new combos, he is weaker than an expert Vanessa, Ramon, and even an advanced K'.
Ikari Team: Hmmm this year it has to be Leona. Yeah, you can player really cheap like in 98, but a Whip is much improved, and the introduction of striker combos help make up for the fact that Clark and Ralf's throws have been slowed down significantly. I think they are all good, but like the Korean team Leona is probabably the weakest link.
Art of Fighting: Hmmm again, this is tough, my say would be Robert, because people still feel that having him as a charge character is a sin, and avoid using him. My Robert is pretty good, EndLeSS can vouch for me, but when compared to the ease of use of Yuri's priority and speed, Takuma's super priority and mind games, and Ryo's invincibility on his DP, robert falls behind as a usuable character. But Ryo and Robert easily change places on this list because Ryo has lost some significant power himself. His counters are neigh useless. His standing b is now a very poor poke. But being a one hit wonder is also lags behind. His 2 hit comboes do more than most C fwd A or Bs into a special, but do less than the same thing into a DM or SDM. Right did I say Yuri? Sorry about that, King is there, and you all already know how strong she is.
Fatal Fury team: Ai...probably Andy...They are all strong again, but Andy lacks the most priority when it comes to normal moves. Mary, Terry, and Joe are all very good, but I think some would choose Joe over Andy.
All Girls Team:
Again, no real weaknesses or weak link here. Hinako is truly a force to be reckened with. Yuri is very strong as well utilizing her speed and priority as well as chain combos. Mai's down B in the air can be abused to utter hell. And I guess Kasumi when used well is very scary as well, but I would have to pick her as the weakest link because of the lag from her counters can easily be taken advantage of.
China team: It's Kensou. After losing his cheese infinity he loses out right to the turtling power of Athena, Chin's d, d B, then up D cheese, and Bao's unpredictablity.
IF anyone actually need anymore depth on these, I can further explain in terms of listing pokes and stuff like that, but then again, that would be writing an FAQ. O_O;