If Ronaldo were to leave then we'd definitely replace him with another striker, someone who would look to score at least 20 goals, because that's basic comment sense as we'd need another starting striker. You can't replace him with Muriel and expect Muriel to score 30 goals, for example, but we've now got goals from Chiesa, Morata, and Dybala will score if he returns to fitness, but you also need 6, 7 or 8 goals from guys like Kulusevski, McKennie, Ramsey (or replacement - De Paul?) and 3 or so each from one central defender, a CM and/or a fullback, etc.
In an ideal world, you'd want to have both. A reliable goalscorer as well goals coming from multiple positions across the pitch.
For that to happen some players need to step up, shoot more often, get into goalscoring positions etc. Currently I only see Chiesa having that (selfish) streak. Maybe that'll happen once we move on from Ronaldo since he takes the bulk of our shots.
Buy on AliExpress.com