A clarification on the grasp-size thing. Currently, what creature can hold what weapon is determined by the overall creature size, which is somewhat limiting. Since we can now determine the absolute size of a bodypart (by correlation between all subsizes in a defined body size), we could swap out the minimum/maximum size tags and the two-handed tag for just one tag, [GRASP_SIZE:X:Y]. The X being the "thickness", or minimum grasp size that can effectively hold the weapon, and the Y being the "length" or maximum size of simultaneous grasps. If the calculated grasp size of a creature is less than X, the weapon can only be hauled. If it's more than X and less than a third of Y, the creature can wield the weapon only two-handed. If it's anywhere between a third and two thirds of Y, the creature can wield the weapon one or two-handed. If it's more than two thirds of Y, the weapon can only be wielded one-handed.
Okay, the above might sound a little too complicated for little gain, but I thought of two cases that wouldn't make sense. A Tyrannosaurus Rex (and similar critters) is huginormous, but has small hands - he wouldn't be able to equip a monstrous sword made for Titans' use, even if he is of comparable size. On the contrary, a magical "floating hand" would be very small - but since it's both magical and essentially a hand in and of itself, it would be able to wield any weapon that a human could wield one-handed. I thought that this bit of "realism" was a logical step forward.