Challenge, that notion is just downright ignorant. The Tiger II, while admittedly being the best line-anchor in the game, is far far more than that.
Move it FOREWARD, and its effectiveness increases unless airpower arrives.. Not only are you completely disregarding the potential for defense in depth, terrain, and choke points, but you're forgetting the psychological aspect of things too.
A Tiger II moving up makes most enemies pull back, and gives everyone else not in a Tiger II a boost in morale.