Would love to see the Winter War portrayed in FH2! But we'd need the community's help in making maps for it. You can always try your hand at the editor and try re-creating your favorite Talvisota map in there.
The most accurate was probably Tolvajarvi.
https://www.artstation.com/artwork/DxDv2n I think they actually went and made a static from the real area for that map.
My favorite from the short time I played was Kuhmo Outskirts probably. The atmosphere of the nighttime fighting was really well done.
https://www.youtube.com/watch?v=CG0824mDPq0&list=PLfiP2VHRI2zsZCnSed7V5jgbvuxOEMYJu&index=8 Aittojoki was really fun as well.
Honesltly, most of them were pretty similar trench sector push maps (to be expected) but they made each of them unique with their own cool lighting and atmosphere. In all, their mod was a great representation of the Winter War imo.