Let's also get is strait was Klopp (who demands high work rate) absolutely fought tooth and nail to keep Countinho. He viewed him as their best player, and he was feared throughout the EPL. Also one of the top 3 attacking players on the Brazilian team. Yeah we were fleeced for price, but that happened because PSG paid the equally crazy fleece Neymar buyout. But Coutinho is a known world class player--and Barca is the only place his impact isn't felt. I think it has to do with the (low) workrate of the forwards and the lack of pace in the other midfielders--so in compounds areas he is not strong at. Put him in City or Liverpool and he would be outstanding--but that is not the same surrounding players and scheme. I also think if we can't play Messi (health or rest), he wouldn't replace him but not too many would be better at helping to offset some of the loss.
Firstly, he isn't world Class, he had one good seaon in 16/17 and that's it. He was always as inconsistent as he is here just go through and check through his game history.
He was the 'best player' in a team that struggled to make the top 4 (lets not also mention their squad was pretty shit back then, regardless i think Mane was just as good if not better) at a time where the teams weren't at the level they are now. He by no means comes anywhere near how important Suarez or Salah were to them as challengers to the EPL/Champions league. May as well apply the same logic of how important a mid table club player might be while we are at it. He wasn't feared throughout the EPL at all...
There were much better options that fit the squad much better then he did at substantially better prices but none of them were Brazilian... So it was a political move made for the boards self interest rather than the clubs. This is one of the reasons we overpaid so heavily so him.
The fact that we received the Neymar money shouldn't mean that we have to massively overpay for any players we purchase.
As for the 2nd part of your post, we've already stated as much, and its one of the reasons a lot of people didn't want him in the first place. He is a good player just not currently a good fit and most definitely not worth the money paid. I still maintain that he shouldn't have cost more than 50m back then, 70 if you factor in the Neymar money....