Ha, I did forget about the lack opera! But you do make a good point, it is hard to quantify what makes the best composer. Beethoven was deficient in some areas of composition for sure.

I would also add that just because you like any one particular composer doesn't mean they don't have some off days! I recently did a Bach cantata that was eminently forgettable... And also I generally like playing Telemann, I never like all the movements in a suite or sonata.