As a fairly strong chess player, but horrible magic player it's always interesting to see comparisons between the two.
First of everything dicemanx says is true, there's definitely more skill to chess than just in-game decisions.
Currently, humans are apparently no longer capable of beating the best computers in Chess – and for good reason, as computers are better at Forward Thinking analysis. A player can’t accurately "weigh" one line of play against another unless they are able to forecast the outcome, which is full of contingency. This is a limitation of basic computer power, whether our brains or central processors. It takes us far longer to evaluate 30+ turn lines of play than it does for a microchip. Computers have already "solved" checkers. It is only a matter of time until Chess is "solved" as well.
I don't think you can argue that computers are better at forward thinking than humans. Any strong human go player can easily defeat the best go computers. It seems to depend on the rules of the game whether humans or computers are better forward thinkers. Also it's not clear if chess will ever be solved, and it's very unlikely that go will be solved.
I don't find your SKILL() argument very convincing at all. What does SKILL measure? What are the units. If you don't specify those, then how can you make any arguments about comparing the different weights. Also, why do you say deck selection, deck tuning and sideboard design require luck? To take luck out of magic you could do something like play with the decks face up and remove shuffle effects [edit: and make players specify their starting deck order]. Deck selection and sideboard selection would very much be part of that game.
At the end of the article you say that magic tests a wider variety of skills than chess (and by implication magic with the luck removed). Seems to me that this statement is obviously true and more convincing then your longer argument above it.
Still, I found the article fun to read.