2fort doesn't give me the farm feel as a map theme would, while sawmill have the "alpine map" feel. i wouldn't equate 3dsky with theme. disable 3dsky on 2fort - what farms lol. disable 3dsky on sawmill - still alpine. farm theme isnt really comparable to alpine theme imo as one is a certain building type and other is basically just green grass with gray rocks.
2fort does still have farm-ish things even with the 3d sky disabled. Hay, silos, cow cutouts, the general architecture, etc. If you can come up with something to call 2fort's environment other than 'farm' or '2fort', I really have no idea what it is.
I'm not trying to say that the detailing in playable space has nothing to do with the theme, it's just that the 3d sky should be an indicator of what the theme actually is.
Finally, farm is probably a lot more than just building type. Flat/hilly area, sparse trees, yellow foliage, and general farm-prop usage all seem like parts of the theme to me.