ty for that, very interesting
So, if a reduction in clothing slots yields no great cost saving then why do they do it? Not just Beth. but Bio. and others.
I think there is a great want for a very uniform way to implement all the outfit assets, See to avoid the clipping and a patchwork look, the art itself has to have certain limitations placed on it, if you wanted all the assets to work seamlessly between sets, then you cannot get very funky with proportions, size, and shape on any one asset. It's a bit of give and take in terms of visual diversity. Any excess clipping is a sin, and you will have that problem at least a little bit, the more detailed the character models are the worse this looks. Perhaps there might be a little bit of developer fear of attempting it. I know that it will drive you mad and limit the art a little. Easy solution: one piece outfits.
Also splitting the assets up into multiple pieces does impact performance, you are essentially creating 5 extra draws calls instead of 1. on and actor which is already a very resource intensive leaf node. Not sure about Bioware, I've not played Dragon Age, but I did read some dev interviews from the character/creature artists. they appear to really want to optimize the character assets.
Game Mechanics and balance I expect woulds also be primary reasons for such a decision. If thats how they want the game to work, so be it. This is why Fallout chose this direction, while technically it has more biped slots than oblivion did (though in game this isn't really how it played out), this is just the way Fallout always was.
Less to do with monetary cost considering Bethesda is kind of rolling in it atm.