In real life most armoured vechiles are useless in the forests or hills, i think armoured units must get penalty for these types of terrains.
what do you think?

Ah, yes... what was it the French said in 1940? Something that translated as, "They'll never get tanks through the Ardennes."? Then, in 1944, there were some who said the same thing, and were once again surprised when the Germans launched the Battle of the Bulge. Even jungles-- the Japanese managed to get tanks through jungles as well. The fact is that few forests, jungles, etc., are so impenetrable that tanks can't operate in them. A better case might be made for marshes, particularly in rainy weather....

They already get no defensive bonuses which is a pretty huge loss. Also hills and forests basically reduce them down to 1 movement a turn just like infantry. Seems like they've modeled your concept in already.