Honestly? Paralives graphics look kinda ass, and that's a GREAT thing. Shows great understanding of their target audience: Women with laptops. If they optimize it well, it'll probably carve out a niche for itself. If they get it to run on potatos and keep the code tight and tidy, they will definitely make waves. It can't be understated how shittily Sims 4 runs, specially when you mix and match DLC content, and how many game breaking bugs you will find over the course of even a very normal playthrough. Custom colors, custom furniture, STEAM WORKSHOP INTEGRATION.
Emerging reactions to the world around them. The paras make opinions and get feelings based on how they see people act and whether they approve or not. That is ambitious. If executed properly their world will feel truly alive, rather than the Sims thing of interacting one at a time or in a small group that all get the same plus or negative rating.
Yeah, these dudes are doing absolutely everything right. Props where they are due. The trailer is also the sort of confidence you only show when you have a good product and you know it.
Sims have gotten really complacent over the years. Dude, you can vary your height in Paralives. That's hell on the animations mostly, but if they go the extra mile, weeeeellllll.
It's one of those things where I thought for years, "Man, outdoing current Sims can't be THAT difficult" and this might very well be it.