For me, especially with marketing videos, a great video is one that makes the viewer understand the point almost without thinking about it. You can have perfect pacing, sound design and storytelling, but if the viewer doesn't understand what they're supposed to take away from the video, all that production quality doesn't matter much. I also think rewatchability is underrated. If the visual structure is clear and there are enough interesting details or a strong payoff, people are more likely to watch the video again. For ads, I'd probably add one more thing: the video needs to work even when someone has zero context. That's a pretty good test of whether the creative is actually strong.