Only just discovered this section of the board, I thought you lot were remarkably quiet on transfer window stuff
Can only say I think the analyses of Souttar here are well wide of the mark and seem to be based largely on the fact that he's a big bastard. But he doesn't really fit the archetype of a big ugly CB - here's what I put on the General board:
Souttar pros: good on the ball, can play out and ping passes, excellent in the middle of a 3 (which I think you play?)
Souttar cons: a bit lumbering on the turn, susceptible to a ball over the top, doesn't look comfortable in a four (which we play)
Overall upper end Champo defender, could do a lot worse.
So while there is truth in him being a bit cumbersome (simply by nature of his giant frame), he's far from slow, in fact at full pelt I'd say he's very quick - he's often able to get others (or himself) out of jail by chasing across and covering. He's also good with the ball, well capable of stepping out and marauding through the midfield to set up attacks, and has a good raking long pass on him too.
I would say it depends very much on the system you play though. As a pair and/or in a high line his weaknesses get more exposed, but in the middle of a 3 he's proper classy.