Grass, shrubs, and trees should not glow as hot as a person or a tank. 2.08 thermals weren't perfect, but they at least did that part right. I appreciate that some changes were made, but this part is not a positive.
Thermals should also see at least partially through most smoke grenades, with the exception of graphite-containing oil-cracking obscurants that require either you be inside a sealed vehicle or wear a respirator.
Fog and rain already appear to fairly appropriately mess up thermals some, as far as I can tell.