I cannot agree with you more. Modules are great for those who like them, but I can literally create a campaign faster than I can memorize a module unless I'm just running the module blind, which I would never do in the first place. The encounters I create will be better tuned for the way I run battles, the entire thing better balanced for the party I'm running for, and in the event I actually forget something I can either check my notes (same time it would take to check the module), or just make up a new detail with absolute confidence because it's my own campaign.
The only thing I really miss out on is pretty maps.