Quick summary of each of the newly confirmed(?) characters' playstyles in DFO in case anyone is interested:
Hitman - Very mobile and flashy (by design, all of the Agent subclasses are). He has a command dash that he can use to evade enemy attacks and then punish with a follow-up attack. He has skills that use his Odachi and skills that use his SMG, and he can freely cancel Odachi skills into SMG skills (but not the other way around). Also, it would not surprise me if they gave him Vergil's Round Trip attack, since he has a similar move in DFO.
Dragon Knight - My baby. Best Girl. Dragon Knight has two distinct mechanics that would really set her apart if they are implemented here. First, she has a pet dragon (Astra) that fights alongside her, sort of like a stand or puppet mechanic. If she uses an Astra skill normally, it behaves basically like a regular attack. However, Astra skills can also be used while the Dragon Knight is busy performing other actions, in which case Astra will go out and act independently of her. Second, she has a flight mode. It works kinda like an MvC-style flight mode, where she can activate it basically whenever to float up high as well as repeatedly airdash around. She has a lot of air-OK skills, and many of her attacks behave differently in the air, so a big part of her gameplay is using abilities that quickly get her up into the air or back down to the ground quickly.
Vanguard - Hard to explain. I guess you could say he has kind of a Killer Instinct-style of combo system. Basically, he has a set of command normals called Smash attacks. He can cancel any normal/special attack into a Smash attack, and then cancel Smash attacks into specials, so they work sort of like linkers. He can also delay Impact attacks by holding down the button, which puts him in a "guard" stance (technically its super armor + damage reduction, not blocking). Overall he would make sense as a bruiser character with big buttons that have lots of armor.
Kunoichi: Most of her skills are Ninpou, which are skills where she can charge them by holding down the button. While charging, Kuno stands in place and performs hand signs which improve the skill, increasing its size and damage. Her skills are really big. Like, "when you party with one, you have to turn party effects off because otherwise the entire screen is always on fire and you can't see anything" big. To make up for the long cast time on most of her skills, Kunoichi has the Shadow Clone ability. Basically, if you are casting a skill and input a second skill. Not only will you cancel into the new skill and start to cast it, but a shadow clone will appear and finish casting the previous skill for you, so that they happen simultaneously. You can even stack multiple shadow clones and fire off like five skills at once if you want. She also has "Cycles of Eternity" which when used lets her record a combo of up to six skills. Then you can activate it and a clone will appear alongside you and perform the combo you just recorded.
Side note: I am actually really surprised that Kunoichi was the Thief subclass they chose, since I assumed she would be the most difficult to translate to a 2D fighting game due to the "everything on fire all the time" nature of her playstyle. If I remember correctly, she was even disabled in PvP for a long time after her initial release in DFO simply due to her being so difficult to balance.
Avenger - I am assuming it's Avenger and not Crusader because the weapon hilt on his back makes me think he is carrying a scythe. It could be the Sader's cross but he usually isn't depicted actually holding his cross in promotional art even though he uses one.
Avenger has a special resource called a Demon Gauge. During just about any Avenger skill, he can press any attack key and a Stand-like, shadowy demon will appear behind him and perform a follow-up attack at the cost of some demon gauge. He can also spend demon gauge to activate a special install-type move called Metamorphosis which is basically a straight power-up that slowly drains gauge while active. He also has a second install move called Demonize, which basically is just Dragon Install. He turns into a giant demon and for the duration almost all of his skills are replaced with bigger, stronger versions, in addition to gaining a couple new moves. In the context of lategame DFO PvE, Avenger can maintain Demonize mode basically indefinitely, but I would guess that in Duel they will keep it as a more traditional temporary install move.