im curious as to why servos and pistons have to be bulky such as afore mentioned samus aran, or even ironman that armor was very durable AND streamlined. just because its motorized dosent mean you have to look like a transformer
You're right. Crysis shows us a rather realistic interpretation of a suit using Electro-Active Polymers (basically synthetic muscles) for actuators instead of pistons and motors, thus the streamlined look, although it does seem to lack any kind of armor plating.

It's a real technology currently in development as we speak, however in Fallout lore the T-51b uses HiFlo hydraulics, which would necessitate a somewhat clunky appearance for the pre-war power armor models involving either pistons or rotary hydraulic motors (round, drum-like actuators).
On the other hand, I think making a streamlined, relatively form-fitting black suit with bundles of EAP muscles visible in the gaps between armor plating would look awesome for the Enclave as well as make it visibly more advanced than the pre-war stuff. And because of the slimmer profile of such actuators, it could be made more recognizably feminine.
Hell, maybe we should just put together an whole power armor pack, complete with female variants, that does away with all the vanilla meshes....
Catsuit... no no that's not what I meant at all, trust me I hate the idea of armor that's supposed to be 90% sexy and 10% functional, sure make it look attractive or whatever but make sure the damn thing does it's job too - the whole 'chain-mail bikini' concept annoys the hell out of me and the in-game Female Metal armor is simply ridiculous - 0% abdominal or pectoral protection, just asking for a perforated lung or gut shot!
What I meant was consider the style but then zap it with the magic Fallout-fashion ray-gun: bulk it up, make it look like it's power armor and not some bodysuit + armor tacked on top.
Go from this:
To this: 
The idea of a feminized T-45d sounds like it'll be great and probably fit the game better, I just wanted to clear up what I meant.
The second pic looks remarkably like a T-51b... Throw the right helmet on with a few other minor details and that would make a great remesh for the boys and a good starting point for a female model.