I've often wished for the same thing, but I'm fairly sure they split it up on purpose. The crossword puzzle is probably one of the most popular features, so ads on that page are more expensive compared to similarly sized ads elsewhere in the magazine. If the crossword was on one page, you could just rip it out or fold over the opposing page and completely ignore the ads. This layout forces you to keep the ads in view, allowing AA to justify charging more than if the ads were easily avoided.

Of course, I could be overanalyzing the entire thing and someone just thinks it looks better that way.