You're right, I DON'T want the Lost Sword - but I'm not going to go crazy about that sword, either.
Dark Curse is just the same thing as Ghost Form, and I'll have the same comment for it: I won't find myself needing to cut damage received...
Snare Immunity, though, will be very useful running through El Sudoron - that way, those Gypsies won't be able to use Grave Shackles on me and slow me down.
Curse Immunity - I don't think I really need this, like Dark Curse. Even with Curse, as a Lv50 player, I don't take too much damage, so immunity to Curse isn't so helpful. For lower level players who just so happen to get this sword ( When it comes out, that is ), it will be a big help. Or could be.
Though the blade is very good looking, that's the only reason I'll really want it