wow I LOVE IT!!! As an avid fan of winter and Christmas, I think you did an amazing job
as sharksheep said, I do think more cedar trees would enhance the place! Since cedar tress look like your standard Christmas trees, it would give more of the holiday vibes
you could also add more items or custom tiles to the mall santa stage, it personally looks a little empty with the space in the middle. (edit: some have said to sprinke some snowflakes around, and I totally agree! it'll also make your tiles look a little more busy but not too busy ❤)
The ice cream parlor could also maybe use some simple fencing? white fence would look super good but acnh has yet to have a pretty white fence ; v;
Of course that's just me, and if you're happy with what you've done, that's what's important! ❤
I was think of wrapped present in mall Santa area and I'll play around with the fence.. ty