When improving a product, many people have an instinct to add features that grab your attention. This usually involves new buttons and sliders. It’s easy to show off that kind of feature, but it’s often bad for the product. Every new control complicates a product. Customers are slowed down by having to learn the controls. The core features that they really care about are obscured by the new glitzy features. Eventually you have an intimidating behemoth like Microsoft Word or Adobe Photoshop.
The best features are invisible. Speed is my favorite. Simplified user interface is a strong runner up. That often involves removing controls. Marketing people howl in pain when they hear that. “Now we have less features to point at in our screen shots!” So what? You serve your customers better through simplicity than through feature lists.