lets look at some shall we?
movement: the heavily armored warrior was slow by comparison to the lighter infantry men. in thicker armor they did not swing sword and axes back in forth at a rate of 4 slashes per second as we have in illarion. in fact there attacks were usually slow and rather easy to dodge. the hard part was taking them down. in head to head combat after a flurry of blows was exchanged the knight was usually onto because of better defense.
field of vision: we have knights who go around wearing helms and acting like there hats. limited field of view in combat was another handicap the knight had to deal with. along with slow turning speeds and movement ability a knight pretty much missed most of what happened on the battlefield. sneaking up on one in the heat of battle would be far easier being his head in encased in a box with a tiny slit in the center.
terrain: the knight killer. anyone remember the crusades? remember why knights were bad in the crusades. armor is subject to it's enviroment, it's extremely heavy and cumbersome on substances like sand. over rocky hills, snow extreme heat. which was the case in the crusades.
now what were the best weapons against heavily armored knights realistically. light swift armor, and a piercing weapon. doesn't sound quite right does it? well faster motion is a huge advantage in battle and percision against a nearly blind target can work out just fine. weapons that pierce were aimed for joints in the armor which were easier to hit then you might think. true the knight in motion might be hard to handle but ti unbending armor areas like the back of the knee for example were easy to puncture. more over with the right amoutn of force applied to a particular point on the armor a knight was easier to toople over. and once his back was to something solid piercing the armor became much easier.
well now i think thats enough for now. but techincal things like this should be taken into account. when thinking about weapons such as those crazy axes and two handed swords which fighters in illarion seem to move by flicking there wrists back and forth. as well as the way they move and fight in those heavy armor. limits for everyone!