SNKPlaymore has updated its blog and they're finally releasing official details on the character balance changes. They'll be revealed in random order in 4 weekly updates starting today.
http://game.snkplaymore.co.jp/official/kof-xiii/blog/archives/2011/10/post_46.html
This translation is a rushed job so there might be some minor mistakes.
It's a damn lot of work too.
UPDATED
Asterisk * notes that the move is featured on the sample video.
http://www.youtube.com/watch?v=YQd_Q_RrCIs&feature=player_embedded
System
Neomax only uses 2 power meters during HD mode (3 meters when not in HD)
Hwa Jai
- All frames on Drink super have been changed (apparently, its recovery is faster)
* Ground CD has changed. Moves forward and has invincibility to low attacks
* Fierce Dragon Tail has faster recovery; can be connected to a normal move after it hits
* Weak Dragon Backbreaker is now a 1F throw instead of a leaping throw
- Weak Dragon Tail comes out faster and connects from a fierce
- EX Air Dragon Kick now hits 3 times like its ground version and does 154 damage.
- EX Dragon Tail chips less guard meter
Producer Yamamoto says: Hwa has a lot of changes, like for example, his Weak Backbreaker is a 1F hit now. The recovery on his drink is different so it might be usable in a combo.
Benimaru
- Flying Drill has faster recovery, normal hit can connect afterwards
* EX Raijinken is a single hit attack. On a hit, the opponent will be stuck in the air afterwards for a limited time. They can be attacked with another move, or even get pushed by running to the edge of the screen.
* EX Air Raijinken lasts for a longer time. The timing in between the hits are longer than the arcade version. It now sort of works as a special that can be "placed" on the screen.
* EX Collider hits less times. That means less scaling for the combo to come afterwards.
* Neomax comes out faster, MAX cancel's timing is different. Invincibility runs out before the hit detection comes out.
- Fierce/EX Super Lightning Kick does more damage. On a full hit, the fierce version's damage has been raised from 70>100, EX from 135>192.
- Collider has faster recovery on whiff, can rarely be punished if blocked from a fierce punch.
- EX Iaigeri > Handou Sandangeki does less damage, down from 263 to 219
Producer Yamamoto says: We've balanced him so that even the attacks that weren't being used in the arcades would be of use. The EX Collider and EX Raijinken should especially come to more use since the opponent can be hit afterwards. The EX air Raijinken should be fun to place around for an attack string. His Neomax has no invincibility but it comes out a lot faster, so it might be fun to think of ways in using it.
Clark
* His Stepping (Forward+BD) is faster
* Weak SAB has full-body autoguard but comes out slower than before
- EX SAB>Flying Elbow can be MAX canceled
- EX Gatling Attack's invincibility runs out when its hit detection comes out. Projectile invincibility doesn't, even after hit detection comes out.
- If Fierce or EX Gateling gets blocked, the Afterattack throw won't come out any more
* Vulcan Punch can be canceled with another move on startup. This allows for some new combos like close Fierce punch (2nd hit)>VulcanPunch>SAB
Producer Yamamoto says: He's a throw character so we've buffed his throws. With moves like his Weak SAB, his front step, and being able to do a super cancel from a 1-frame throw, he should be able to fight like a real thrower.
Mai
- Kaschousen comes out faster, also has quicker recovery
* Ukibane (down + B in air) has different trajectory than Arcade, recovery time has been changed
* Musasabi(from ground) can be canceled to Floating attack
* WK>FK is a chain combo. Can be used to connect into HD mode, and also gives Mai more damage on pokes
* EX air Shinobibachi added in game. Invincible until hit detection comes out.
- Crouching FP has more cancelable frames
- Weak Ryuenbu has more vertical hitbox
* Neomax comes out faster and freezes time when it reaches the edge of screen
Producer Yamamoto says: We've balanced her as a female ninja by giving her attacks that can make her fight more tricky from the air. Using Ukibane to trick the opponent and doing an attack string, or hit confirming from her crouching fierce punch have become effective tactics. Her Neomax has also been buffed.
Leona
* Voltec Launcher chips less guard meter
- Strike Arch (directon move) comes out faster
* Fierce V-Slasher has different angle; weak travels short, fierce goes far. EX version is the same as the arcade.
- Ground Saber has longer recovery when blocked. About even when fierce version gets blocked.
- Moon Slasher has less hitback when blocked. All of them (weak, fierce, EX) are easier to get punished than the arcade.
- EX X-Caliber comes out faster. Still can't be comboed from a normal or direction attack.
Producer Yamamoto says: Moves such as the Ground Saber and Moon Slasher are easier to get punished so be careful. We've balanced her so that she can do things such as attack strings with her EX X-Calibur, or break into the opponent with her Strike Arch. Her Fierce V slasher has been buffed, and she's a character that's good in various occasions such as air-to-air combat or against projectiles.
Takuma
- Jump CD comes out faster
- Stun value on attacks has been lowered
* EX Kyokugen Koou comes out faster and has quicker recovery. Still can't be comboed from a normal or direction attack.
- Fierce Ryuuko Ranbu comes out faster. It's still slower than the weak version, but it has invincibility until after the hit detection comes out.
- Weak Hienshippukyaku's damage reduced from 70 to 50.
Producer Yamamoto says:
He has less stun values than the arcade, but he's still easier to dizzy the opponent than other characters. Also, it's not written above but damages on his other specials have also been raised, and he's a character that can do high damage. He's been buffed in a lot of places like his air CD and invincible Fierce Ryuuko Ranbu, so please try using him.
Mature
* Ebony Tears comes out faster. Can hit opponent afterwards
* Weak Metal Massacre is a one hit attack
* EX Deathrow correctly puts crouching opponent into hitback state on a hit unlike arcade version. If the opponent is crouching during 1-4 hits, a fierce Metal Massacre can still combo with a drivecancel.
- EX Despair doesn't move Mature behind the opponent even if they're crouching
Producer Yamamoto says:
Ebony Tears is a lot easier to use now. Weak Metal Massacre has been changed to a single hit and does less scaling, so it might be useful for fast paced matches.
Shen
* Gekiken Fakeout has faster recovery. It'll fail if the kick button is pressed too soon.
Gekiken maxed out will chip half the opponent's guard meter
* Danken(throw) comes out slower. Neither weak nor fierce has invincibility. However, it can be Drivecanceled.
* Danken(reflect) builds up meter on a success. No drive meter buildup.
* EX Fukkogeki>Kouryuugeki has slower recovery when blocked. Completely punishable
Producer Yamamoto says: We've did a lot of adjustments to his Danken. The throw version is no longer 1F, but it can be drive canceled for additional damage. Gekiken's feint has quicker recovery so it can be used to lengthen attack strings.
Actually, some nice tradeoffs. V-Slasher has become better at punishing from distance, so overall happy. And Strike Arch should be a more effective mixup. I hope Grand Saber's blockstun isn't WORSE than it's been in any old games, if it's about equal to older ones, that's ok. 
