So Mainoo isn't blazingly fast. Nor is Bruno, nor is Casemiro. If you were to compare passing progression, on the ball progression, defense, and speed between our four mids:
Passing
Bruno>>Mainoo>=Casemiro>>Ugarte
Carrying
Mainoo>Casemiro>>Bruno>Ugarte
Defense
Ugarte>Casemiro>Mainoo>Bruno
Speed … man tough because we have a bunch of people who have a tough time running people down, at least at this stage of his career for Cas; I'm certain he did it all the time at RM. I'd guess:
Bruno (not as fast as he used to be, though) > Ugarte > Mainoo > Casemiro
FWIW, my impression of Baleba is: very very good speed (real fast, not just fast compared to our midfielders), very very good carrying, good defense, ok passing (he will never be Bruno, but it is decent to good, certainly better than Ugarte). If you wanted to compare him to Caicedo at Brighton, he is ahead in speed and carrying, behind in defense and passing. That's why I've said I like him a lot… but, man, if Brighton's number is 100M, he's far from a finished product. Big number. But he's a great athlete.
Anyway… I kind of think Amorim wants fast midfielders. Just an impression, hard to say since we don't have fast ones. So I'm actually not sure he will ever love Mainoo.