Ronaldo still remain the best,he was their best player last season,and if not that he is unwilling to play for United again,he could still perform well if he wants to.He just doesn't want to play for United again because they are not playing champions league football.But if I were to be United's coach,I would use Ronaldo because at his best,no defender can block him from scoring goals for his team.
Their coach should make him to form a solid partnership with Sancho and Antony to get more goals for Man u.If they can use the three of them consistently upfront,then I believe Manchester United will have one of the best and sharpest attack line in the premier league.
I don't want to say that Ronaldo has played badly this season. however, in fact we can see how when Manchester United had to lose 4-0 against Brenford. at that time ronaldo became the main starter and played full. then just because of his desire to leave Old Trafford, it's as if he's not playing seriously.
I don't think so, the fact is that none of the big clubs are really interested in using his services until the transfer window closes.
In my personal opinion, Ronaldo's performance has greatly decreased, we can refer to the match against FC Sheriff.
Ronaldo didn't do much, his performance was not very impressive. in theory the main starting line-up has been as you said, but that's the fact.
I do not doubt the skills and talents that Ronaldo has. but he must really recover his form until he becomes the main starter again, both in the premier league or Europa competition.