I wanted to use the new Legion Zero Vigiles Guards on an outfit build today, and I spent hours trying to get a decent color combination to match the dark red part (fur?) at the sides of the guards that can't be changed (which is already difficult by itself due to the colors applying like they damn well want depending of the armor piece, but oh well). And even when I *mostly* managed to do it, it still looks like **** half of the times because that dark red color is way too dark, and in darker environments it just looks like it's almost pitch black, ruining your outfit no matter how well you've chosen your other colors (unless you go full Goth, of course :P).
Not to talk that I've been waiting for a long time for the Windhelm Scale Tunic Shoulders to be dyeable, and we still can't dye it :P
Please, even if you've to link some part to another (like that dark red fur to the leather strips above it), that'd be preferable to having locked colors. At least we'd have the freedom to change everything more to our tastes.