I agree with Aleksandr. The Berdiche Axemen are great infantrymen! Their armour uprgrades quite well, too!

I use them as offensive infantry, if they are killed, they will bring down many, many enemies with them if used properly.
Their poor defensive skills can be circumvented by using them in conjunction with other Russian units. They go well with just about every ranged unit and cavalry. Tactics with:
Cossack Cavalry, Boyars Sons, Kazaks Use your missile cavalry to shoot at the soon-to-be-attacked-by-bloodthirsty-russians-wielding-berdiche-axes, preferably from a place that nullifies the shield.
Dismounted Dvor With dismounted Dvor, just shoot from the front as these guys cannot normally get on the flanks to shoot.
Tsar's Guard, Druchima Get behind an enemy, and after the enemy engages with your Berdiche Axemen, charge from behind!
Dvor For Dvor, use the Light Missile Cavalry Tactics (#1) with the preceeding tactics so that your Dvor shoot at the enememies' backs and charge. Make sure to stop shooting after the Axemen have engaged, as that can cause unnecesary casualties. Then, charge!

The tactics seem simple, but they are very effective.