The combination of modern snow tires, stability control and an even weight distribution makes the RWD Model S into a capable snow car. The Model 3 will be lighter but I would guess that it would handle about the same. Yes, AWD plus snow tires would be even better, but it isn't necessary for ordinary driving, assuming that you are reasonably careful and the snow isn't too deep. Roads here get plowed and sanded promptly so it isn't usually a concern. However, my long, steep, curved driveway is a challenge in winter even when it is shoveled. It sometimes gets icy and stays that way for days or weeks, but the S plus snow tires worked fine. It changed my view about RWD Teslas.
If someone is a first responder who has to head out into a blizzard, AWD would be preferred, although I would think those folks use high ground clearance SUVs or trucks.
AWD has other advantages in better range and better handling, but it comes at a cost. And if you lose the full tax credit — assuming that you qualify (I don't) — that cost will be a bit greater.
Some Tesla drivers set the regen to low when driving on snow and ice to prevent regen braking from causing a loss of traction. I don't bother with that but I use the regen gently when conditions are slick. I think it is more of a problem with neophyte snow drivers who go too fast for the conditions, and then compensate by pulling their foot all the way off the "go pedal", rather than feathering it, and end up with too much regen braking.
