how was Link vs Marth bad? well yeah, it was the 1st one ever, but think about it:
Link had a shield, lather and chainmail, as well as a wider sword to block/deflect/lessen the blow of marth's slimmer sword. Whereas link's master sword could probably cut to Marth's spin from the side seeing as he had no armor, and it was heavier.
Who had the deadlier blade in that scenario?
Oh forgot the chainmail.
Regardless, I think you're making some assumptions about the Falchion. It's slimmer, but even though he's wielding it badly, it's definately a longsword.
http://www.youtube.com/watch?v=7zu2z7GVQHY
Sorry about the spoilers.
Those things were made to batter people to death in full platmail. The chainmail will help with the slashing damage, but the bludgening damage is gonna honestly kill Link.
Honestly, yea, I did forget about the chainmail, but I knew that it should have the heft to deal deadly damage if hitting the center of mass, I knew it did, but I didn't realize by how much, because I honestly didn't remember it was a longsword till now.
Also... BTW the difference in reach between Marth and Link is quite large.
Link's sword is less then half his body length. Marth's is almost as long as his body, that's a major difference.
Both blades are deadly on hit, close-range, marth gets a definate advantage, but Link's projectiles give him the overall edge, granted, they limit him in close range.
Edit: This also gives some insight into how tall they are, I'll explain if it becomes necessary.
Edit2: It initially looks a lot shorter then it is because it's at an odd angle, but check out when he actually HITS with the Falchion.