From the way Klopp talks, it sounds like the transition to the #8 position is a permanent one for the foreseeable future for Minanimo and it's probably the right move in this situation. Clearly the biggest problem in his game is the inability to hold on to possession when challenged – I think there is no other player in the squad, including the youngsters, who gets shoved off the ball more easily than Minamino. So the only way to help him regain some confidence is to move him back, where there is more space to turn, the pressure is less fierce and there are more teammates around to lay the ball off to. Klopp did a similar thing with Lallana and it worked; Lallana is famous for his turns and Minamino's signature move is receiving the ball on the turn. Playing at #8 will allow him more space to do that and to play his natural short passing game, while his tireless pressing can also be an asset, as we saw against Midtjylland.
So Klopp seems to have found currently the best position for his misfiring attacker, but is it a step forward for Minamino? I think it's more of a step back, but a necessary one. It's an acknowledgment that the original plan and the reason he was signed – to supplement our front 3 (or front 4) and become a quality understudy to Bobby – has been a failure. Playing at #8 in those occasional appearances will probably allow him to regain some confidence, where his creativity will once again hopefully shine through, but we hardly need another neat and tidy midfielder and by my count there will be 7-8 players ahead of him in the pecking order in that position: Gini, Keita, Hendo, Thiago, Jones, Milner, and possibly Shaqiri and Ox as well. So he won't get a lot of playing time other than cup games and "garbage time" in games that are beyond doubt; for his sake he should use that time well. He needs to get stronger and learn from the likes of Gini, Salah and Jota how to ride challenges and use the opponents' aggression against them.