Longswords were and are NOT heavier than Katanas. Some examples might be, and vice versa..but on the whole they all weighed 2.8-3.6 lbs. Of course there are outliers.
Katanas are better at slicing because of the curved blade. Longswords were unquestionably better at thrusting due to the highly tapered point....Kind of the way it appears now in game exactly!!!
Yes, Katanas were not as good against metal armor, because they were not designed to emphasize a thrust. A slash or chop would be less effective against metal armor. The metal armor that Feudal Japanese soldiers used is much different than the metal armor European soldiers used. A katana would not be very effective against an opponent clad in a plate suit, but it would deal better against a samarai in metal armor.
Now were all getting in to it. I love realism subsugestion forum, tis the only place other than spam everyone can freely talk utter shit :D That is directed at me, and everyone that isn't having a rage black out as they read this thread, those that allow themselves to be amused by the absurd.
Onto a serious point!
Garison, you said "Longswords were unquestionably better at thrusting" I have a crapy youtube video that begs to differ. Really though these 2 swords are very similar against heavy armour, to the point where it makes no real difference. A katana will blow away the Long Sword in a cutting fight with crap armour but once you step up into scale and plate the 2 weapons platue out and the only real difference at that point to the killing power of either sword is in the hands of context and that is all.
There is a lot of jingoistic white power bullshit around this EU vs Asia sword debate, I've sat on both sides of the fence. Its almost rascist. But its mostly just ignorance.
Who here can put there hand up and say "Here is scientifc trail of both swords vis a vis thier capacity to blow armour into bits/killing power" I sure as hell can't and I doubt anyone else around here can.
I've used both and they both seem perfectly capable of fucking up your day. I got the same results from thrusts and cuts out of both, the only real difference was the Katana kept going through tougher stuff. The long sword dented an old Ford's bonet wish a slash and the Katana left a hole in it, not much of one but it was thier. I'm not sure what to put that down to, I think its the curve droping more force onto a smaller point.
TL:DR enough of my gable now to begin the dueling youtube videos!
http://www.youtube.com/watch?v=EDkoj932YFo (http://www.youtube.com/watch?v=EDkoj932YFo)