I can't comment much on Leo, as I don't use him/her/it. Miguel I did - very pitbull-ish character. He's fun to play, Trust me.
Lars is... very different. He's nearly about as odd as Steve when he appeared in T4. Lars has a spacing game that is similar, in a sense, to saying that Lei has a mix-up game. It's unusual.
Apparently his full name is Robert Richards (confirmed). He's like a "torpedo" SF fighter remade into 3D. You get the feeling you're playing somebody Blanka/Honda/Bison-ish, but with all the right Tekken-friendly tools.
He also has a wavedash.
Uhhh... what roots? T1 had Devil with a laser beam. Jack the vertical flying cyborg was already in T1. Then there's Yoshi's teleport (T2 IIRC), and a host of other things. Tekken's always been an OTT 3D fighter.
Jab carries have been the norm since T4. Nothing new there. As I mentioned, the bound moves are essentially extenders - any move that's quick enough will connect - high, mid, or low. It's rather addicting though. There is a sense of having 3 parts to the combo: the initial juggle hits, the bound move, then what you can pull off post-bound. The damage scaling is such that you really can't get 50% without a wall or CH anyway, so it's really a "style" thing (and "stylish" combos have been around since TTT, so again, this is just an evolution).
Also, I failed to mention that some bound moves can catch tech rollers, and placing them in bound. This benefits (and balances) characters that don't really have crazy good oki, like King (his db2 elbow hammer will hit a backroller, bound, and then he can do a spinning powerbomb).
Item moves are taunts. Nothing more. Think SF3 Shaun's basketball taunt. They're slow as hell, do very little damage, and are easily avoided. Although it's good for a laugh if you think you can catch your opponent sleeping (e.g. they're on their last bit of life, and are running away thinking there's nothing you can do to catch them, and then you slowly pull out your gun, and shoot.) I've won twice this way, and the looks on their faces are priceless.
Hell, I've seen a Kuma vs Asuka match wherein Kuma whiffs the roll, and the Asuka player wins via archery shot to the back. Samurai 1, Mammal 0.
The game is top tier, believe me. Balanced and fun, and the fights are BS-free. Gone are all the T4 Jin unblockable laser scraper, 21 abuse-type moves. Zafina is pretty much the weakest character, but people still take her to tourneys, so even then, it's not that bad.