I do agree this would be a good idea, although at the end of the day this is only possible with those with ERG modes (which is probably not the majority of the zwift riders - I have a dumb direct drive myself).
On a more general note, I do wish that Zwift would implement more tests altogether, be it only to test fitness levels & gain more information on one’s strength and weaknesses, as well as ideally to customise workouts even further.
I suggested it some time ago, albeit with little support from the community and no answer from HQ: Tests other than FTP (VO2 max, peak power, sprint power, ...)