Thorn Gulley

[AJaW96]

While it is true you can rush with the heavy, it is a big risk. You might take out their soldier, but if the opponent successfully counterattacks then your are left with nothing defending your base. Because of the distance from spawn spaces it can be difficult to reinforce with troops in time before they rush you back.

The above comments are very general, but the big point is that unsupported heavies can be dealt with.