Used to think pruning was just about looks, but my basil plant proved me wrong. Let it get tall and lanky one summer and it barely made any leaves. Started cutting it back regularly and it turned into a thick, leafy monster. Totally get the mint thing now, some plants just need that tough love to actually thrive.
Ugh, @adam_wells5, you've nailed it. My rosemary did the same thing last year, just a wild, woody mess because I ignored it. But a few careful trims and it was full and usable again. It's funny how the plants we use the most demand the most attention. Mint is just the most obvious, and pushy, example of that whole deal. A friendly little tyrant.