If only we could invent the verbal equivalent of a trapdoor function. A word puzzle that would be extremely easy for computers to generate and humans to solve (since we understand language), but extremely hard for computers to solve.
It's a nice idea, but you have to consider the complexity of the word puzzles compared to the average human's brain power. Most people are quite dumb. If there aren't a sufficient number of problems/answers, or they're simple enough for computers to solve, or they're too complex for a minority of humans to solve, you're boned. The whole thing is a technology arm's race. The best solution would be one where you simply…
I know what you're trying to say here, but consider today's xkcd[0] as a counter-point. I think "most people" are quite capable of solving a lot of puzzles. This issue is that any puzzle that we can solve in a reasonable timeframe is often a good target for a computer-generated solution as well.