While I should be pleased that most of the universities I have been attached to have done well in your world rankings, all the talk about "the best universities" sounds more like selling soap powder. The rankings gloss over the fact that if different measures were used, or with different weighting, different results would be obtained.
Peer review sounds very much like the old-boy network. How many of these people asked had English as their first language? Maybe this correlates with the preponderance of English-speaking universities on the list.
The fraction of overseas students could be argued to be an indicator that the universities are prepared to lower entrance standards to accept lucrative fees. That scenario would help explain the bizarre ranking of the Australian universities.
Why should overseas staff be a measure of performance? If a country produces its own high-level academics, why is it better to recruit from overseas?
But no choice of weightings is going to give you a ranking of the best universities unless you first define what is meant by best.