Alright, first of all, this thread is supposed to take a quick overview about melee weapons, the use of these weapons and what are clichés we should get rid of.
We'll kick the can with our first cliché:
What's the other side for? The other side of the axe is just extra weight and encumbrance you put on it. Most of the time when you swing you'll turn your arms before the next swing so you'll automatically have your axe's side pointing at the right side. Also, if you swing it back to the other side without turning your arms, your blow will become much less harder and thus less effective because you can't use your shoulders enough to swing your arms. A pick as other side is acceptable.
Now we go on to...
Greatswords... In the sense of 'great'...
Now I see this many times, those one-handed swords with a quite oversized blade. In some cases it is quite acceptable, like when the character uses the blades of a bastard sword on his one hander sword, but ranging from twohander swords to 'unrealisticgreatcumbersomesuperbreakablebutubersh iny swords'. After a swing or two, your arm muscles will already begin to feel the effects of swinging a really unbalanced blade, and that is not good, because you never know how long a battle might take. Also, another comment on those really unrealistic fantasy swords whose blades have the size of a human including it's width while they are still being carried with one hand.... believe me, even with using two hands those things will handle really slow. Also, they are extra breakable, swords are no lumpy clods of steel; real swords are fine pieces of steel who are a little bit flexible as well.
Another annoying factor:
This subject is a little more difficult, but it be overlooked. Ok, armors CAN be pierced, penetrated shattered, even with swords. There is NO such thing as "The unbreakable armor made by my father the blacksmith lalala...." Unless those armors are 'magically enchanted' they can be penetrated. A sword may be more unlikely to pierce it, but from a correct angle and a good blow, armor may just protect your life but not your flesh... Also, there are armor-piercing melee weapons, like axes, pickhammers, halberds, etc...
Armour ALWAYS has weak spots: Plate armour often leaves the armpits, neck and crotch open, mail armour can deflect sword slashes, but harder cuts especially from armor piercing weapons will shred that mail armour. Also, mail armour is more vulnerable to arrows.
Oh, arrows, I almost forgot. Short bows and/or recurve bows have small chances to pierce through fine plate armour, bows like "The Welsh Longbow" have a fair bit more chance to penetrate armour, and Crossbows, especially with steel arms, are THE medieval equivalent to anti-tank missiles.
And last but not least:
Give it up, shields are not entirely made out of iron, NEVER. Except some few exceptions like buckler shields, but they are thick and not suitable to cover from arrow fire.
Shields are most oftenly made out of wood with some leather over it. It stops arrows fairly well, but keep in mind that the more arrows your shield catches, the less able you'll be to use that shield. Those arrows replace the balance point of your shield, making it a LOT heavier. Shields eventually break too, especially when they get battered by a two hander axe or something brutally like that.
So. I'm fed up writing with this lot information. Might add a bit later, but here are some main points and stuff.