Coming from someone who has only ever been a 2hander, and only recently made a polearm alt, I have to agree to disagree. While I will say that the lolstab is OP, it is also "hard" to do. Whenever in a duel I always glance off of people when trying to stab them if they are anywhere near half the length of my sword away. It might have to do with me always having lower powerstrike though, I'm not sure. I will say that it is incredibly annoying when it happens to me, but i have only pulled off a point blank stab once or twice. As far as the curve-around-the-back-of-your-head-stab...I have never noticed myself doing one, but have definitely felt its affects many, many, many times. However, it seems that we are ignoring how ALL stabs are like that *cough polearms cough*. The pike is definitely the worst offender.
As far as the whole "2hander deserves to be the strongest melee unit" argument goes...well, I kinda have to agree. We are absolutely powerless against any and all ranged, having only footwork and the surroundings to save us (or a helpful ally). However, unless you group in polearms who use poleaxes and such into your definition of a 2hander, then I must say...polearms have the same strengths as a 2hander, but no one complains about them. MAYBE most 2hands swing faster and are unrealistic. But if that is the case how hard do you think it would be to swing something that weighs 2-3 times as much, with all the mass concentrated on the far end? If 2handers would become realistic, polearms would be near useless. A normal poleaxe would have to be swung at the speed of the great long maul, if not slower. Not to mention polearms get more variety, as well as viable secondary modes.
As far as buffing archery, I will just say that shooting around a shield is enough of a buff, and should be implemented to some degree. If the shielder cannot rotate and position his shield properly to face the archer or cover his head and such, then it would be rather unfair and archers would get pretty easy headshots. You have to remember that us 2handers with no defenses can still easily get picked apart by even the weakest of archers since all they have to do is shoot us, turn, run, hop, shoot us, rinse and repeat. Happens all the time and we are defenseless. Increasing their strength would of course be more realistic, but suck... a lot.
And in regards to allowing for overhead stabs.... yes. it should happen. Happened in real life, and is a cool mechanic that would make the class much more viable. However, my only gripe would be that they would become twice as strong. Sure, it isn't THAT hard to charge someone who outreaches you and block up and down, however I have already seen an increase in the numbers of pikesmen recently, playing support all too well. All it takes is maybe 3 pikemen in line with infantry to scare off the opposing team. Why? Well, cav wouldn't go near, and the opposing infantry wouldn't either. There is nothing more annoying that fighting someone, only to be stabbed by 3 different guys who you didn't even see since their range is so great. If they could attack in two directions, then they would not only be pure support, but also an incredibly ranged fighter. Sure, in a 1 v 1 maybe the guy with a 2hander or poleaxe or 1hander could close the gap (assuming they can block well) and win. But in a mob, or 2 pikes v 1 infantry, the pikes will have a significant advantage of range. It is hard enough closing the distance on a skilled pikemen as it is... with the spin-jump exploit and all... it would be a nightmare if they had two modes of attack. But once again, it should be implemented, I just fear there may be balancing issues following. (of course a shielder may be able to still destroy an enemy pike by easily closing the gap... but since shielders move slower, and if that pikeman had a decent amount of athletics...)
Summary / tl;dr: If 2handers are to be nerfed, so must all similar classes i.e. the infamous glaive or polearm users. Personally, i found the glaive to be easier to use than any 2handed greatswords simply because the range was about the same, but it didn't ever glance, it was faster, had the same power if not more, and also has stopping power against horses (while you have to be really really good with a 2hander to even attempt standing up to a charging cav *half-swording buff could help here*). Shielders and pikes should be changed to add more variety to the game.
By the way, am I the only one who has noticed that when shields don't utilize their magnetic pull ability, throwing weapons or arrows will simply disappear on impact, thus not even damaging the shield? I noticed this for the first time when I tried throwing (which I won't even bring into this argument) and was pretty shocked at how often it occured. Aim anywhere near the brim of the shield and the game almost doesn't know if it hit or not, so the projectile will stop at the contact point, then fade away.
End of rant.