Think Mac Allister has been fine as a 6 but isn’t the ideal profile that would usually suit the Klopp system. We all remember Klopp saying that our team was very offensive minded when we signed Endo and we needed someone like him. Generally speaking that’s what every top 6 for a premier league side needs to be, someone that connects the back 4 and midfield defensively, can take away the central zones and usually slip in at centre half if one of the centre halves pushes high or steps up. There’s nothing wrong with saying Mac Allister is a good 6 whilst saying he doesn’t really have those qualities in abundance. His distribution, technical reliability, industry and general football IQ means he can do the job there really well, just like a Wijnaldum could and Henderson could, it wasn’t their best role, though, but sometimes it was what was best for the team at the time.
I see Mac Allister’s best ‘role’ as a bit like a Modric. Ideally he’d have someone more defensive behind him, you want him to have a bit of freedom to find the space, resist the press and play the right ball, I genuinely think he has the potential to be in that bracket of midfielder. However, if he has to play 6 to get Jones and Szoboszlai on the field then it’s probably the right move for the team as they both bring so much to the 8.