Just a few thoughts on the legendary status equipment stuff...
I take it there are four kinds of levels of equipment; regular kind of equipment, with literally nothing special - improved equipment, with fairly standard stat boosts - special/unique equipment, with interesting/unusual features - and finally legendary equipment, which is just bossly beyond compare. Sort of like improved + special at the same time.
It's been said that Lucina's and (the late) Saito's swords are both legendary. I don't know about the Mercurial Blade's stats, but I'd guess that both it, Boomeraxe and Meister's Soul are special/unique weapons. Of course, it's perfectly possible that the Mercurial Blade is a legendary weapon. Something like Composite Long Bow +1 would be an improved weapon, which most good-level players would now have at least. Regular equipment is pretty much just mob drops for our characters. Amirite? I half feel like I'm playing an actual game, here :p
Also, if there are those kinds of levels for weapons, do they also exist for armour and clothing? Perhaps even special full weapon and armour sets that give boosts for being used in tandem. I'm just recalling playing Dungeon Siege II now, and having full sets of equipment that gave you crazy boosts if you could find all the pieces. A thought came to mind with the Mercurial Blade - although a mercury-like substance seems cool for a sword, I get the impression it would make some really good armour - tough and easily wearable at the same time.
Heheh, safe to say, guys, I'm thinking of going into a career in game design when I get older.