because its overpowered at 4 Other, costing less than most weapons and dealing more damage than the most powerful one, giving up the shield doesnt mean much with crusaders and animate weapon.
consider, this is stronger and faster even adding momentum than using titan with crusaders.
its just too strong at this cost, make it at least 6 Other if not 9.
it should be faster cheaper easier to use blessings and titan and such, in looking at the library of cards, this is just too powerful at this cost.
i still think it should grant some protection, you can block and keep attackers away with a polearm, its why they are on poles. probably block the opponents weapon. great card but its too cheap as it is, and it could use more sophistication.
look historically at the halberd, they are not giant axes, you dont 'swing' a halberd, you cut poke and drag it across the opponents body. you block with it and keep swords out of reach. its actually more of a defensive weapon. The power, cost and overall structure of the weapon needs reworked a bit.
i like the card, but feel it could be much better with further revision. id say cost 7-8 and stops equipped weapon attack damage other than titan.