Team Ninja is still alive and kicking. They just don't have Itagaki, unless all the team left. I can't see that all the following games show team ninja at the start:
They made Nioh 1 and 2 (amazing games if you haven't played them).
Rise of ronin.
NG Sigma 2, Sigma 2 plus (vita)
NG3 and razors edge
NG master's collection.
I did play through Ni-Oh 1 and 2. They were OK. The combat was fun, but everything around it was kinda bad (story, graphics, loot, level design).
Also I'm still not convinced the souls formula is a great fit for third person hack and slash with emphasis on combos and stylish gameplay (which maybe Ni Oh wasn't that much).
Then there was Wo-Long, which I thought was the biggest heap of trash. It was everything that was wrong with Ni-Oh turned up to 11, with a dumbed down combat system and really boring levels.
Rise of Ronin I haven't played.
Let's also not forget they co-made Yaiba, a zombie based ninja game, which was atrocious.
NG3 when it launched was a travesty which I forced myself through. RE helped it a bit but you can only polish a turd so much. These games are boring, sterile, and lack the NG magic.
Then there are the various remasters and re-releases, which is probably the best thing Team Ninja has put out in the last decade compared to their actual "new" games.
I just went and rewatched the trailer for NG4. It seems the main protagonist has dual blades that fuse into a single blade...that then expands to get longer...wtf
Like why can't we just have a fucking NG game where you take Ryu from 2, give him all the weapons, turn gore to 11, get rid of all the childish demon designs, add some more weapons, add some more bosses like Murai (ninja vs. ninja battles work SO well).
God damn do you even remember the first battle against Murai, just walking into that room and having him bitch slap you with those 'chucks till you had to get gud? Hold me daddy.
Nothing TN has done since those golden days comes close to that.