I never understood the merits of a "completeness" discussion
In football, all that matters is your contribution and your effectiveness. It's silly to put any significant weight on completeness is a holistic sense because as you move further away from goal, the skills become less relevant. Suppose some other guy is a better keeper than Messi....could we knock him for not "being complete" because of this?
The concept of completeness is both nebulous and overrated. Shevchenko was more "complete" than R9. He was better in the air for sure. However, Ron was simply more brilliant and was a more dangerous player
The point about Messi not being as complete as CR7 is moot....because though CR7 is faster, stronger, better fk taker, better distance shooter, better with both feet Messi's vision more than compensates for not being as good because he has that rare ability to create goals for others. He's just as effective as an old-fashioned #10 as he is as a #9 and is almost as good as a #7 winger/support striker. Then there is the dribbling. He's better than CR7 at it. So much that everybody knows what/where he's going (see Arjen Robben)....and nobody can stop it.
Since I am old, I will further elaborate on this point using the examples of Pele and Maradona.
Pele was more complete in the sense he could and did use both feet, was strong with header.
Some people say that Maradona used only one feet and was not that good with header, hence Pele was better. But to me, this reasoning does not seem good.