Polearms weren't effective in stopping charges in MT:W either. They have bonuses of 3/1 vs. cavalry as opposed to the 1/4 of spear and 2/6 of pikes. Their defense wasn't that great, either, so they would knock out quite a few cavalry if charged but they would get massive losses. In melee, however, especially if attacking the cavalry's flank, they would annihilate cavalry quickly. It's a good balance as you would still need spear units or anything to occupy the cavalry units for these guys to kill them.