Does Valencia actually often beat his man? He seems to me to have maybe pace but no acceleration, he tries tricks but rarely beats his man with them, doesn't link up with other players well and while he's done a few nice crosses, plenty of turd ones, he wins corners, but from what I've seen hasn't been very good at all.
Wipe out everything you remember from him in preseason, look only at his(and Nani's) performances since then, has he really been anything other than average on his best game? When I heard Utd were getting Valencia I thought, not Ronaldo but decent. But when I try to remember that outstanding stick out performance he had for Wigan, I can't, at all. I can't remember a truly great game, and other than a couple goals I can't actually remember him being very good at all.
I think he did a Hleb, was great in his first few games when no one knew how he played, got a couple early goals and assists, got his reputation, then did smeg all the rest of the year.
I still don't really rate Rooney as a striker, yes he's gotten goals, but unlike end of last year where he was great for 90 mins, he's mostly drifted in and out of games, getting crucial goals sure, but could have not been on the pitch for 80 mins in more than a few games this season already. You need him on the ball running things, not up top with Nani/Valencia trying to get him the ball.
I said it last year, theres maybe too many average players in the UTD team and Ronaldo made up for a lot of lacking quality elsewhere. Remember Ronaldo might hog the ball, but he also had the ball pushed it up the pitch almost every single time, which relieves pressure, pegs the other team back, stops them attacking, makes an easier game for the defence. His final ball was excellent, or he'd win corners, or score. Nani breaks, the team rushes up, then you get caught on the break.
A lot of what Giggs is doing, is just keeping the ball and keeping the other team from attacking, which is invaluable.
EDIT:_ FrankJH, remember, even on an off day Ronaldo could score 2 and get 2 assists, which he has done. So even if he's playing badly, you can be VERY sure the entire other team is still playing with Ronaldo in mind, meaning they leave less space behind, they commit less players forwards and that still helps every player on Ronaldo's team. Likewise, his worst games would often coincide with being double man marked, you're still doing your job for the team, one more man marking Ronaldo = one less man elsewhere for Rooney and co to take advantage of. He was also invaluable at your own set pieces, won lots of defensive headers at corners again preventing the other team from scoring.