Think about this logically. Forget Neymar for a moment.
Every top team in the World want or need a player able to penetrate defences through:
1. Providing width with pace
2. The ability to dribble and beat his man 1v1 consistently
3. Being able to operate in close spaces, as most players are good when they have a lot to work with
4. Being aware enough to run into space behind defenders to receive a pass in a good position or pull the defence out of position
Do Barcelona have a player like that right now?
No.
Messi can do 2 and 3, but he's not one to provide width and the danger behind with a sudden burst of pace.
Can Suarez and Griezmann do it? No. I don't even need to ask the question for Coutinho and as for Dembele then he's not even able to control a simple ball, move off the ball into space or do anything with defenders putting pressure on him.
Almost all of our CL rivals have someone with this profile. Even if we change our manager, we need a player with this profile.
Even with a better midfield being able to counter press, we need someone to work the ball into, to threaten the opposition backline and force at least one of their FBs to stay a bit more conservative rather than bursting forward all the time.
If not Neymar, then suggest me one player with all, or most of those characteristics that will improve the team right away.
There's a reason Bayern want to sign Sané, and are desperate to sign him with Man City holding out for 150m. Hazard might be a bit overweight right now, but he has a deceptive burst of pace with the ball glued to his feet.
Sterling is good and getting better at it in Manchester every year. Liverpool have Mané and Salah that can do that. These are probably our closest CL rivals.