Okay, time for me to take a stab at this issue...
While I can see where some of you are coming from, you really need to take your heads out of your buckets and take into consideration that when the devs said it's to make one, deep customizaiton system, they really meant it.
As others have stated, their workload would instantly be doubled for this. Some have brought up RPGs as counter-points, but I don't see any of them having a movement(and thus animation) system as complex as Brinks. Take into account that for all of this to work on males, they had to make according meshes that were weighted to their skeletons well enough so that they'd not animate weirdly during all those neat tricks you perform via SMART.
First is that you have to apply this to -every- piece of equipment that doesn't match vertex-by-vertex. Considering the sheer ludicrous amount of choice you get in Brink, I'd say doubling this workload would be crazy. Secondly, you can't forget everything else that ties in with this. What made SMART and the characters' motions' relation/insertion/creation process a long headache is that since you get to play against A.I in non-MP modes, they had to make sure the A.I is capable of using SMART: not necessarily a problem in terms of separate skeletons, but it's just very time consuming. Look at how long it took STALKER to be developed partly because of the A.Is complexity.
I'm sure you can see where everything starts to tie in together and how it becomes apparent that indeed, time constraints are a very, very severe issue. I've seen people bring up the comparison to "but game x used the same skeleton for both genders/it wasn't a problem"...to you, I present, first, this image of Femshep sitting(ignore the motivational text, best shot I could find in a hurry):
See the issue there? Even if not all females have the decency/care to not spread their legs while sitting idly, it still looks awkward in a general perspective. And while yeah, that's only for one sequence in ME2, it sticks out. People have made threads on BioWare forums asking for them to make sure the female animations in ME3 are of better quality. Now consider that due to biological differences, females and males don't look the same when they perform complex acrobatics...if Splash Damage stuck to one skeleton and called it a day...well. It'd just look goofy, and I'm DAMN sure people would whine incessantly about how the devs were lazy with the animations even IF say the female characters were as insanely customizable as males.
And again - it would double their workload, which I admit would not be as big of an issue if the SMART system didn't call for -so many complex, accurate animations and calculations clientside-. The mass of work going into Brinks already solid framework was, logically, willy shriveling in breadth.
I hope I got my point across on why time constraints would've made an equally badass customization system creation and polishing process a complete mess(not to mention the end result would've been sloppy).
FYI, I do make 3d models and dabble with animating them. While I'm no pro(not even mediocre), it's still pretty obvious how difficult it is to make just a handful of different designs look good and animate well on a scale as big as Brinks.
