New hidden blade
Alright, so I have a really strong feeling that theres going to be a new Hidden blade allowing new moves in Assassins Creed 3.
This is Altair's Hidden Blade Schematics
Altair's hidden Blade allowed maximum stealth and didn't really pack a punch/ didn't need to since armor back then wasn't very good. The blade's shape was more thin and long
Ezio's Hidden Blade Schematics editted by Da Vinci
Ezio's hidden blade allowed for armor penetration and increased damage. It also allowed the user to open and close the hidden blade quickly. Remember Ezio's move to rapidly stab someone's stomach? The blade was slightly thicker and somewhat shorter, allowing Ezio to do more rapid attacks
Assassins Creed 3? Idk, But I'm sure it will allow a lot more possibilities
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A new blade seems likely and I really hope there is a new design 
It's pretty difficult to imagine how they might change it but it better be cool 
"Death, the most dreaded of evils, is of no concern to us; for while we exist death is not present, and when death is present we no longer exist." Epicurus
I hope it is only a single blade, and the other wrist has a silenced gun and pellet shooter (smoke pellets) and the poison dart shooter. The actual blade, though? It would be cool if it could split apart like opening scissors when the blade was extended, which could make for brutal assasination animations and allow it to act as a grappling hook if they want to go that way. (contrary to what people say, I think that a grappling hook could work if it didn't have a very long range and could not be used unless standing on a flat surface or in the air, (only if there is a beam in front of you if in the air.) a good control for it could be Lb. Gonna start a topic for this, thanks for the idea dude!
Ummm ok? I don't see how that's a whole new idea... but you know...
Idea: JUST CAUSE CREED 3! Lol, no grappling hooks. That would ruin free-running. 
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Unless you gain the ability to punch through drywall and assassinate through there, there's not much further you can go with the hidden blade. Whatever imaginary mechanics Da Vinci and Altair had in their designs don't matter.
I didn't think it was a new Idea, I just started the topic for general weapons.
AC3 should have a bit of exposition where an Assassin weapon-maker explains how the bloody things work! I see no visible mechanism being triggered, Ezio just spasms his hands.
Yeah, AC2's blade is bollocks. AC's works with a ring on Altaïr's pinky.
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"Hopefully it [AC3] will make us feel like an ASSASSIN, not an errand boy that kills guards in between getting milk for his arthritic stepdad." - JoeyFogey
I'm guessing spasming your hands in a certain way pulls on a trigger connected to the bracer. It seems like it would be tricky to not trigger during freerunning. If it's strapped to your arm, however, it should be easy to stretch a trigger.