Though, there were weakspots in the armour, where you can go with a bladed weapon, and blunt and heavy weapons can still do damage.

It was only really when firearms became practical that armour became worse, before then it was a good all around protectitive device

http://en.wikipedia.org/wiki/Crossbow

Good idea with the hammer by the way since the mace was intended to get by the armor by bashing everything inside of it while leaving the armor intact. A crushed arm cannot wield a sword against you. The voulge, bardiche and halberd draw their power against armor from physics. remember that the weight of the weapon will increase its impact and when that impact is on a very small point such as the end of a spear or the edge of a blade it can cause tremendous damage. A thrust or slash is not likely to do much but an overhand swing that lets the blade travel and gain speed adds to its momentum and thus increases its penetration power and if it fails to penetrate will still bash the heck out of the target. Consider the distance traveled in a spear thrust, probably only a couple of feet. But the arc of an overhand swing lets it travel for a few yards (several in the case of a long pole-arm) before reaching its target and it also has the added benefit of gravity assisting the blow.
anyhow, the weapon you want is the poleaxe since it was meant to breach plate and the head of the weapon is three weapons giving you added versatility. The spear to brace against a charge, the axe blade (or hammer depending on variant) for slashing/smashing. and a spike on the opposite side of the ax blade/hammer for piercing the armor.
My favorite method of dealing with plate and heavy armor comes from the steppe horsemen. that is the use of a lasso to catch and then drag the stupid SOB wearing plate. Knights are an incredibly effective tool of warfare but they lack versatility and especially mobility when compared to even the hun riders, let alone the mongols’ golden horde. Historical note, the only reason the mongols didn’t conquer europe is that they arrived too closely on the heels of the barbarians’ invasions of rome and none the cities they scouted had any real wealth (consider that they were used to raiding the very developed cities of the chinese and other asiatics) and the few battles they did fight were incredibly one sided, so much so that to this day Russia still remembers and hates them for it. Though the lasso is a fun way to take down a knight the mongols would more often just shoot the horse out from under them. The scots liked to do a similar thing to british chivalry except that they used the claymore to hack the horses legs off thus achieving the same goal.