Even if you DO use WEU in a map to get more cliffs, you'll need the WEU game patch to have the map work...
Suggestion ---
This probably, will make something that looks like a cliff.
Okay first, put some tiles on the map that you want to be turned into a cliff...
Second... Raise the height in the area of those tiles...
Third...Use the plateau tool to flatten those hills...
Fourth...Put pathing blockers to block ground units from going down the cliff...
>.<