I've always fancied him here for us for a few years tbh. He has a keen eye for a killer through ball and is obviously dynamic on the ball. Very close to Iniesta who we need to legitimately find a long-term replacement for. We can't repeat what we did with Xavi with Iniesta, and I think someone like Coutinho will be key to keeping Neymar here long term, especially post-Messi.
The problem however is in MF, we need smooth outlet balls from deep positions. Particularly last night at the Anoeta but also in other games this season, we have struggled to make a clean first pass out from our defensive end. It's all on Busi to do that, teams are suffocating him which is partially why he hasn't looked himself this season and this problem is why I'm kinda done with Rakitic here. He was abysmal against Sociedad, was not dropping back quickly enough and was woefully inaccurate in his passing. That's unacceptable in the position he's in and this is a big concern in this squad because we really still don't have that guy for us in MF. I'd need to see more of Gomes in Raki's position to be certain but so far, I'm not convinced.
On the other hand, I've liked what I've seen from Denis and Rafa so far and their progress in particular will determine if we should go for Coutinho in the summer, because we won't get him in January. The question then is if Coutinho will be a definite upgrade on both Rafa and Denis. If not, then can he play in the deeper positon, which from what I've seen from him, I'd be skeptical at best of him performing well there consistently.
He's complicated. I wouldn't mind him here at all but he would force some MFs to leave (which I'm not against at this point) and in all honesty, Veratti is the type of MF we should be targeting. Him, Bazoer or Tielemans are really who I think fits the bill for what we are looking for.