Pike easily outreaches glaive with a stab, too...whats your point?
Glaive - 3 good attacking directions, outreaches all greatsword attacks but the stab
Pike - 1 direction, low damage, cumbersome, unsheatable, 3-slots
Greatswords - 4 good directions, 1 outreaching almost every melee attack in the game. High damage, good speed.
I fail to see how your comparison makes any sense... I think the glaive is quite a gay weapon, but it's not really better than the greatswords.