I've only seen him a few times but for me, he's more suited to the 8 role that Klopp has promised Coutinho (which makes the whole situation even more interesting) rather than Lallana's interior role of a 3
May even ****** Henderson off his workhorse B2B role
A nice headache for the manager, but let's see where Klopp see's him as a fit (should he sign)
Outside of the 'keeper and back 4, nobody really has a 'set, defined' role under Klopp. As he says himself, numbers are more for the starting formation and defensive shape without the ball. With it, it's all about fluidity and change of movement. For example, Henderson (when he's actually healthy which is getting less and less to be able to rely on him regularly), is the #6. But he's not ostensibly a DM/ playmaking deeplyer in a traditional sense. Yeah, he'll drop in there, often between the two centre half's who split wide, but he has licence to get up the other end or move wherever he sees fit. With someone else then dropping in. Which goes for the all the front 5/6. Someone like Mane may start the right, but he could be anywhere through a game with then Firmino or Lallana or whomever switching over. It's all very intricate and takes a lot of getting down so it's hard to really define set positions per se in Klopp's L'pool. And he's already mooting becoming even more tactically flexible formation wise next season.
Phils not been 'promised' a deeper role. That's the very last thing Klopp would do as Milner has found out. He'll just be there when the formation and personnel dictate. Other times he could be pushed further up etc. Just adds a new dimension to that tactical flexibility.
Which all makes Keita even more appealing as he's been used in a multitude of roles by all accounts his career and been dominant in them all.
I don't know how to answer dilakh as it's horses for courses and opposition dependent, and not least as I've not had anywhere near a good enough look at Keita. But presuming he's better than what we have, and the manager wouldn't be after him or anyone else if he didn't feel that, then as a three I'd say Keita, Coutinho and Lallana would be the ideal choice.
One thing's for sure, an already real strong, varied midfield group would get even stronger if/ when he arrives.