I think this definitely comes down to personal Opinion.
The Sims 3 snow's roof texture is hideous imo, looks like something you'd see in an early 2000's game.
The Sims 4's also looks bad, but I do like that they made parts of the roof visible through the snow. It's not just a static texture.
The Sims 3's snow texture on the roof is literally terrible and is super Low Quality.
Neither games do it as well as they could, so it's not really a huge loss. If The Sims 3 actually looked good by comparison, I would be annoyed.
Also, The Sims 3's snow DOES NOT suit the semi-realistic graphic style of the world,
while The Sims 4's suits the art style.
The Sims 2 probably did it best, and even then it looks pretty bad:
http://thumbs2.modthesims2.com/img/7/9/3/4/3/0/MTS2_monmel_891602_snapshot_36cb9cb5_56cba262.jpg
It's probably something that causes a lot of lag, so they are maybe extremely limited with it.
