I kinda hate to say this, Daniel, but so far I haven't seen any actual sword art or system that I would consider a legitimate, or even viable system from any Korean source. And, once again, this one is included.
To take each of the examples given here one by one;
This, frankly, was terrible. The drawing looked likely to remove fingers, the sheathing was likely to damage the scabbard, sword tip, or both, if not simply miss entirely and skewer the user's hand, the cutting was incredibly bad (with the right hand doing everything, and the left hand essentially "dead", which meant it had no support to allow cutting, far less power than what is possible, a "pulled" angle on the sword making an off-line cut, and more), incredibly odd use of arms in postures (the right arm almost locked, the left very bent, again a hallmark of the poor cutting mechanics) and much more.
If I was judging purely on this example, I'd say it's someone with a few weeks experience of a Japanese system, and they didn't stick around even long enough to learn a semi-decent grip. If someone like this came into my school, they would quickly be informed that they had no idea of swordsmanship, and would be taken straight back to the very beginning immediately... and they may find that everything they thought they knew was based on nothing.
Okay, it must be said that the Korean arts have always been very good at their demo's , and this is again no exception. Very clean, and significantly better than the previous clip... however, still a lot of overcutting, a fair amount of, shall we say, combatively illogical movements (to put it gently), some rather dangerous habits involving the drawing and sheathing of the swords... and did I see a blatant rip off of a Katori Shinto Ryu kata? Methinks I did.... (Gyakunuki no Tachi, Tachiai Battojutsu, for those wondering... but not that well done, sadly).
Some okay stuff, but sadly most of it was not very impressive at all. The first clip (the cutting of the bamboo) was terrible. The first cut was over done and muscled, the second cut was off-line and ineffective, and the third was the first all over again. As for the rest of the clips, "cutting" paper the way it's being done isn't really anything at all, the kids sparring was kids having fun, and the cutting methods in the kids learning were again deeply flawed.
What do you know, if anything, of the art? So far as I have seen, it does not appear to be overrun with twirly-twirls or "I just saw Revenge of the Sith" material. It actually looks fairly reserved.
[URL="http://www.youtube.com/watch?v=5kCgWf7X-TA&feature=related"]http://www.youtube.com/watch?v=5kCgWf7X-TA&feature=related[/URL]
Agreed that this is fairly reserved compared to most of the others of it's ilk, however it's not swordsmanship. This clip shows again many of the issues I saw in the first clip, unfortunately
And, as for not seeing "I just saw Revenge Of The Sith" material, from the third link you provided (last clip):
[yt]32mUM_1B53c[/yt]