Exactly my opinion as well. Seeing as we won't find better than Neymar for the left-wing, we should definitely be improving multiple positions to make up for that. If Coutinho is the only player we get to replace Neymar, we are indeed undoubtedly weaker than we were last year, which would be dramatic for the club. Ideally, we'd get Verratti + a ton of cash for Neymar, which we would then use to get two replacements for Ney (possibly in a 4231, but I'm not sure it's doable). I'm thinking Dembele, Coutinho, Dybala, Hazard (according to Marca, we might make a move for him, but I have no idea how trustworthy they are. I would personally love to see Eden in a Barca shirt, but I'm probably biased being Belgian and I think many people here would disagree with me) or even Mbappé, but he's probably out of reach.
The only thing I'm liking so far is the fact that we seem to have more depth than last year (thanks to the signings of Semedo and Deulo, and youngsters who seem ready to step up their game such as Alena, Samper and Marlon). But for now, this whole Neymar-saga has me stressed out.