I think adding a motion blur effect object would make games feature more realism. The type of motion blur I thought about was a part moving at a certain speed, a helicopter propeller, a spinning top, or even the camera’s movement speed. It could also complement the feature for it to render decals, textures, Surface Guis and thing mostly in the category of a surface image. As well, for it to have options to apply blurs to a rotational/spinning blur (e.g. helicopter propeller), a movement blur (e.g. bird moving past you fast), or both. This feature would be especially useful for people who want fast moving or rotating objects to look fast and more smooth, regardless of frame rate or lag.
I recently saw another topic that better explained how this could be used, here. The topic also goes over properties that could fit this feature well.