Orange: Added an option in View Properties panel to disable drawing of 'relationship lines' - i.e. the dashed lines that connect objects in parent/constraint/hook/IK relationships. After talking to the others I rolled the Armature-specific one into the same setting for simplicity's sake. We can see how it goes, always possible to put it back.

source/blender/makesdna/DNA_armature_types.h

@@ -95,7 +95,6 @@ typedef struct bArmature {
 #define		ARM_DONT_USE    0x080
 #define		ARM_MIRROR_EDIT	0x100
 #define		ARM_AUTO_IK		0x200
-#define		ARM_NO_PARLINES	0x400
 
 /* armature->drawtype */
 #define		ARM_OCTA		0

source/blender/makesdna/DNA_view3d_types.h

@@ -127,7 +127,7 @@ typedef struct View3D {
 #define V3D_MODE			(16+32+64+128+256+512)
 #define V3D_DISPIMAGE		1
 #define V3D_DISPBGPIC		2
-#define V3D_SETUPBUTS		4
+#define V3D_HIDE_HELPLINES	4
 #define V3D_NEEDBACKBUFDRAW	8
 #define V3D_EDITMODE		16
 #define V3D_VERTEXPAINT		32