As a photographer who has photographed countless weddings, I've experienced every possible outcome of wedding photography. The less-than-perfect photos often happen because of a few different reasons.
The first is the most obvious - bad photography. When you choose your photographer make certain you've gone through their portfolio. Do you see anything you would like your wedding photos to look like? Because if you don't, that photographer probably isn't a good fit for you.
Make sure your photographer knows their stuff, has lots of experience, and is informed about what you want EXACTLY. If you hire a photographer who focuses on black and white, retro noir kind of photography, and you expect full color with lots of modern effects and nobody discusses how the photos should look, guess what will happen? You'll end up with photos you didn't want because it wasn't discussed before the photos were taken. Be specific, talk to your photographer, and make a plan.
Check out my blog post to read more tips and secrets to getting the BEST wedding photos possible, no matter who you choose to do them!