I am interested in this game but some questions I hope you people will answer me
Before... I never played a Samurai Showdown before but I love KoF and SF.
How is the gameplay?
the gameplay I have seen is more close to the 2 mentioned above as to let me say ArcSystem games which I like but on the other hand don't enjoy the fighting system that much.
I'll try to help a bit! Lets see...
The popular feeling is that the gameplay is less about combos, more about patience and reading your opponent. This shifts a BIT depending on the character you play, but it's still prevalent throughout. The majority of robbing matches from your opponent won't come from setplay and comeback tools, but more through patience, good reactions, and forcing impatience out of your opponent.
Fights are generally grounded and spacing based. You'll be testing your opponents ranges with weapon strikes, and trying to only use the strong strikes when you know they're going to hit.
The universal systems are closer to KOF, in that you have runs, dodges, and quick backdashes. Pokes are more like traditional SF, in that they lead to simple followups, rather than MAX Cancels.
You won't see ASW things like IAD or universal AA normals here, though. There is a once per entire match Rage Explosion skill, that's similar to GG. You sacrifice your meter for the chance at a super-strong single-use attack. But if you miss, it, and your meter, are gone for the remainder of the match, not just that single round.
Are there some previews out?
After the disappointment I made with MK I do not want to spent money blindly again just on hype.
Is there something special to the franchise as well?
Depends on what you want out of a preview. The trailer in the OP of this thread is the best official product overview. Most other places focus mostly on specific characters, or a single piece of news. However, news outlets all over the world (IGN Korea, IGN USA, Famitsu, DengekiOnline, etc) have all had a few cracks at gameplay overviews. They're mostly just impressions of the things all the live demo builds have shown us, however.
As far as something special to the franchise? There's lots, depending on how you look at it. The series was the first Weapon-based fighter, it's probably the first at all with "pet" characters, the old-school scene scaling was very impressive (it has a bit now, but it's not obvious), And it's story timeframe is somewhat unique, and overall well realized. It's also violent but not SUPER violent.
As a modern fighter now, it'll probably be one of most "traditional" of those out now. It's low on noob-friendly hand-holding, it's execution is improved but not super-simple, and it focuses more on perfecting the necessary, rather than tossing out a lot of extra bells and whistles. Though there have been 7+ Games to the series, this one closely resembles the 2nd game, with a few things taken from the later iterations.