Its tough to say, i would rank some keys more valuable than others, and almost to the point that some keys promote other keys, but this is inherent in the persons ability to play golf. Yet there are other aspects that might take into account.
If i had to rank the 5 keys in terms of importance
Flat Left Wrist
Diagonal Sweet Spot
Club Face Control
For me at any level, the ability of a golfer to perform the 5 keys is inverted
Higher handicapers would be able to control the clubface, it easy to open it up at address, learn the ball flight laws, ect. This is the easiest to learn and implement.
I almost willing to throw out diagonal sweet spot, because really good golfers can play with a pull, or pull cut.
Flat left wrist, i almost say can be helped out by the top two, because if your weights back, you got to loose the flat left wrist to hit the ball first. So, in some regard that is controlled by the top two as well.
That's the graph i think represents key's versus handicap, Since there will be ranges of handicaps that have maybe 2 keys, that is shown there vertically from 10-15 handicap. To me this represents better than a single dot, fitting a curve to the line. Because we are representing whole numbers, the graph should be a step function.
Also, the reason why i have 3 keys going out to single digit handicap is because i wanted to show consistency of the having 3 keys. Meaning, they might be able to perform such keys 80% of the time, this shows the inconsistency of the player and the reason they might look like they have a solid swing, but end up shooting higher. Does this mean they don't exhibit 3, 4, or 5 of the keys, no, it just means they are not as proficient as a professional or another single digit handicapper.