Much will center upon how the affirmative defines the terms in the proposition, most importantly "superior" and "excellence," since both imply valuation, as well as what competition and co-operation mean.
If competition means unrestrained war of all against all, then the argument will take a different turn that if competition means "within established limits or following the rules." And is competition only on an individual level, or is there such a thing as "team competition" (building the first atomic bomb, for example, or debates themselves or college bowls)? This applies for co-operation as well, because who is co-operating is important for a "successful" outcome.
To complete your logical argument, since there is no "rule" for such a condition, you would have to prove that, somehow, the cause is superior to the effect (in this case existence), a dubious metaphysical or even scientific proposition.
The affirmative, I should want to add, has the luxury of defining the terms of the resolution; at the same time, they must defend their definitions against charges of unreasonableness from the opposite side. I should think that your qualms about the wording being slanted might be alleviated by careful definition, and by drawing clear boundaries about the range of the discussion at the beginning. One of the problems I see for the affirmative is that, without such boundaries, the opposite side can bring up all sorts of different counter-examples that would be difficult to argue against. It is the difference between asserting "all" instead of "some" instances meet the resolution's position.