When designers first learn discipline, there’s a tendency to cut anything that isn’t the strongest gameplay experience. That gets you 90% of the way there. However, it’s possible to throw the baby’s rubber ducky out with the bath water while keeping the baby herself.
In small doses, variety trumps quality. Try eating your favorite food every meal. It quickly becomes unendurable.
The same goes for gameplay. You want players engaging with your best, most satisfying, most polished gameplay most of the time. However, including some highly different experiences keeps things fresh.
A good example is when designing a series of gameplay maps. Maybe you make 10 maps, and one is clearly the best. Great. Use it and variations on it most of the time. However, every now and then use one of the other very different maps. The novelty lets you reset your gameplay taste buds.