Played the hell out of it today. It's Tekken 4/Tag style gameplay. Sidewalking is still possible as in 4, backdashing has been increased as in Tag but characters now have long range throws to counter attack this.
Flaws The tag juggle system returns. Whilst 60% combos seem to be the most damaging, walls ruin the game. Tekken 4 at least had a wall tech roll. Tekken 5 does not. Hence a combo leading into a wall can cause up to 80% damage. On top of that when a character lands from being comboed into a wall he/she is open to a free ground hit from the opposition which can only be just frame tech rolled. Expect 90% combos by those who know how to use the wall. Pro's will begin a juggle in the middle of the stage then jab, dash, jab, dash, jab, dash until they reach the wall then finish you off. Remember this is the whacked Tekken 3/Tag style juggle system, Julia can easily sneak in 6 elbows from the 1 juggle. The only advantage is that you can select the level. Don't pick one with walls unless you yourself know how to abuse it.
Walls aside, I think the game is fairly balanced. King and Marduk have been upgraded with the ability to perform catch throws or air throws, a Tekken first. This leads into some very satisfying and flashy juggles, my current King juggle is simple u/f+4, 1, f+2,2 f,hcf+1. King performs a hopkick (which is the juggle starter), jabs once, performs 2 powerful right jabs, then catches his opponent in mid-air with a running powerbomb. King has 5 catch throws at this stage.
Previous character animations have changed as well, don't expect Julia's 1,2... strings to look the same, or Kazuya's 1,1,2. Many old attack strings not only look better, but some have improved properties and some have many more options.
Throws can now be escaped very late in the animation, sometimes the character whose throw is escaped is left in vulnerable posistions such as the back turned position. A Tekken first.
VF's customisation system is available. I've seen some pretty sweet customisations. A Kazuya player with a totally different hairstyle, with red hair, sunglasses, red samurai shoulder pads and red pants. A Kuma player with star sunglasses and a fisherman's hat. Roger Jr with a snorkel in it's mouth and flippers on his feet.
If I remember more, I'll post it later, but that's all for now.