It’s a great idea. By pushing the design in the extreme opposite, you create a larger conceptual area to work within, and you also expose opportunities to “break laws” of convention. It’s also a different way for your brain to work on the same problem… It’s like filling out two columns (bad & good) rather than just the “good” column we tend to focus on as designers.
I always like to put together 2-axis region maps that defines the category of whatever I’m working in. (One of the most common in the design world has emotional/rational on one and complex/simple on the other.)
One of my favorite books on creativity is “Jump Start Your Brain” by Doug Hall. He’s got about 40 creativity exercises and one’s called “Law Breaker.” It works this way: you list all the laws, truths, perceptions, myths and absolutes surrounding your task, and then next to each law, you list one or two ways to break it.