Cyprien is an interesting link.
He looked good as a young player emerging in that Lucian Favre, Nice team.
Then a combination of things happened, first he got a horrible (ACL I think) injury. Then Favre went, Nice lost some good players like Ben Arfa, Ballotelli, Seri, Mendy, Plea, Pereira, Saint Maximin, Sneijder, followed by Vieira coming in with a much more pragmatic brand of football, and through this he was gradually playing his way back from a serious injury.
I quite like what I've seen of Cyprien, he has a decent rounded skill set, technically good, good engine, can move with the ball and pass it, but he's not the pure footballing 6 type we are craving, he's more a box to box type who likes to bomb forward, and he's not the most tenaciously rapacious. I think he's actually a better player of his type than Soumare at considerably cheaper.
As a kind of utility (hybrid) midfielder he'd be a big upgrade on Sissoko, but what we need is a new improved Wanyama.