One of the bad ideas mentioned before in the name of "armor diversity" is the pervasive notion that plate armor turned one into a dexterity-challenged hulk who would be lucky just to raise his weapon arm.  In that same vein, chain provides less protection, so umm it must allow much greater freedom of movement, right?  Wrong.

A suit of chain was in fact typically lighter than a suit of plate (some 30 lbs. compared to around 65 lbs.), but a chain hauberk has terrible weight distribution.  All of the shirt’s weight falls on the shoulders of the wearer, and on the wearer’s head in the case of a hauberk with an integrated coif.  Think about wearing a jacket with 30 lbs. of lead weights hanging from it and you get the idea.  On the other hand, articulated plate is custom-produced for the wearer by a master craftsman, and weight is distributed fairly well.  Articulated plate keeps its shape in bizarre circumstances, too.  It is fully possible to do cartwheels in full plate if one is strong enough.  The same cannot be said for chain.