I know there's been some discussion of genetic mutations that may have increased its spread/infectious capability, but lessened the severity of the illness. I think the proof will be in the data, hospitalization rates, ICU rates, etc. Those don't lag THAT far behind new cases, so it won't be hard to see. But there are confounding factors, the largest being the (younger) age of those being infected right now, and perhaps next being the experience and tools now available to the treating doctors to prevent more serious and fatal disease. I've not seen anything published that demonstrates reduced virulence after accounting for those factors.
Here are two recent articles that say just that.
Some mutations have no effect, while others could impact transmissibility.
www.livescience.com
France has seen a sharp rise in the number of coronavirus infections in recent days. But the surge has not been matched by a rise in severe cases admitted to hospital, as has been the case in other countries.…
www.rfi.fr
Hawaii, being a relatively small "lab," is actually a good measure. We can watch cases and patients in the ICU.
https://www.hawaiidata.org/covid19 If the number of new cases stays steady ~100/day, but the number in the ICU gradually drops (it's recently dropped, but that's likely from the drop in cases from ~250-300 to ~100) that would evidence a less virulent disease.
That said, there is a natural selection for less deadly forms of a virus, since a dead host doesn't spread as much virus as does a live one. So you'd expect "evolution" to favor a mutated form that produces a less severe disease as it creates more opportunity to spread (called attenuation).
That said, if you're at risk, you don't want COVID, or the flu. Either and both can be fatal to a person that's got co-morbidities such as COPD, diabetes, compromised immunity (as most people 75+ years of age have), etc.
news.yahoo.com
