This is just another difference i have noticed between the WC3 and APEX's version.
The wards in WC3 version could be placed with ease through 2 layers of trees or on top of a cliff (OUT OF LINE OF SIGHT) with no problems.
In addition to this, the wards also gave vision of buildings through (i think about 6 layers of trees) - when i say vision here i mean they got to see if new buildings where built or there were buildings in the fog. Hmm sought of hard to explain. How you scout someone's base in a melee game and then your probe/drone/suv dies, you still can see the buildings and any new ones that popped up.
Finally i think the wards in WC3 had a much larger sight radius when unobstructed.
Not saying that APEX should implement all these changes to make exactly like WC3 version as its only based on it, but may help these struggling thors..