Yeah I agree. Problem is people see it like Casemiro is playing > Casemiro is a CDM > Casemiro is to blame for lack of protection of defence. It's not that simple. Look at how high he plays at times, this doesn't lend itself to him shielding the defence and is not making the best use of him. We signed him for what he did at Real and then threw it all in the bin and tried to reinvent him as a player. When we were signing Amrabat and Ten Hag said he can play behind Casemiro, alarm bells were ringing straight away. I just think Ten Hag is a bit of a plonker in all honesty and I wouldn't trust him to get the most out of what is an extremely talented squad.
Funnily enough SSN were just running a comparison of Ugarte and Casemiro, comparing the number of times they lose possession, number of times they're dribbled past, number of tackles and interceptions etc. Ugarte was marginally better in all areas (though the PL will be a substantial step up from Ligue 1 - so a pretty unfair comparison). But they were talking about how Ugarte will be being signed to 'plug the gap' in Casemiro's place. Well yeah, that is partly true. But like you said, Ten Hag can't just play them in like for like roles and expect Ugarte to be able to shield counter attacks when he's in the opponents box on turnovers. You'd have to be a blend of Usain Bolt and N'golo Kante to do that. Yet nobody talks about the tactics or the way Casemiro is used a lot of the time. It's frustrating really, as it's not really his fault entirely with how last season went.