I don't think Nzonzi is significantly better than Coquelin. I'd rather have Guendouzi and Torreira who can grow with the team.That's why we need players like N'Zonzi to make us a top team again. We haven't been a top team for like 7 years, that's why change was needed - we're like you lot as Liverpool before Klopp joined the club.
We need new wingers though badly. And new fullbacks + CBs. Basically the whole back 4 needs to be replaced.