I would compare Nicholas Sparks to James Patterson in terms of how they work, both know what sells and aren't interested in exploring anything outside. They've found a formula that seems to satisfy their audience and can just re-use characters and situations ad infinium and their readers don't seem to mind so they have no incentive to be creative.

Sparks isn't at Patterson's level of laziness yet, where he just hires interns to write his books for him but you still know exactly what you are going to get with a Sparks book everytime.

It's cool that you enjoy his work but be aware that there are writers out there who do what he does with a lot more originality and skill.