This is all on Valverde.
Name ONE player who has blossomed under Valverde?
I see Coutinho being the same as Pogba was under Mourinho...uninspiring, lazy and just not good. The most important thing is to first get rid of EV and get a manager with a more attacking, free flow mentality, and someone who has the balls to actually play with at least one attacking midfielder and doesn't just want workhorses in his midfield. Maybe put Coutinho there instead, and he will start to flourish once again. He's certainly not a traditional, nor world class winger in the mould of Neymar, that we had. And with Dembele seemingly cementing his starting spot and Suarez and Messi being untouchable, not to mention Malcom waiting in the wings too, there's no better time to change pace, shift some players around a little, and see how they pick up their form. But again, unless and until EV is gone, i don't see Coutinho anywhere else than LW.
And it's not just about Coutinho. I'll bet you almost everyone in our team would get better under a new coach, breathe some fresh air into them and let them loose to show their attacking potential, don't limit them like the coward that EV is.
As for Coutinho, if he still doesn't pick up his form after all that, sell him to PSG or back to PL for 100M+ next summer, i think we need to consider that too, but that's a long way to go, like i said, first step is getting Valverde out, then seeing next season, which players are actually worthy of staying here, we can't judge them too much under a bum like EV.