There are definitely many people who had no or extremely mild symptoms, and there are also many people who have no (known) after effects. But - I'm not sure whether or to what extent those populations are being studied - and that can cut both ways. If those who are being studied tilt towards worse symptoms and/or obvious after effects, then the risk of having after effects could be overstated. On the other hand, if the healthier group doesn't know they have after effects (they don't recognize them, they don't seek medical attention, etc.), then the risk of after effects might be understated. But I suppose that is an obvious point, and can apply to almost any virus, disease, condition or treatment for same. (I had some time during an MRI this morning to think "I wonder what the long-term effects of this will be?" Then I thought of something else.)
Just anecdotal, but I got over my C-19 (and pneumonia that was either caused by, or coincident to, C-19) in early July and still have a ground glass opacities in my lungs (that I only found out because of a chest X-ray unrelated to C-19). It's still too early to tell what GGO means in this context, but I don't think it's good.