I am a engineering student, and I just started working on a project looking at lower extremity (legs) body armor. I thought the best thing to do would be ask people that would use it what would be good, and what would be bad. The last thing I would want to happen is come up with something that the brass like, and make regulation, but is impractical and a pain in the field.

Some starting questions would be:
Mobility is a good thing. What is the worst thing to have to deal with: weight, bulk, or stiffness?
What gear is carried on the legs?
What threats are the main issue with legs (IED vs small arms)?
Plates? Just soft armor?
Thighs vs shins vs both?
Out of the products already available for the legs, is any of it used?

These, or anything else that you could think of would be very appreciated.

try to research new materials not at popular discussion. some of the most resiliant materials are soft and give a lil.

example being that nasa is currently thinking about building further space stations out of purely a cloth that is not only air sealed but can withstand the impact of meteors, it is so strong.

certain sheep and spider web blends can be more protective than kevlar.

just look into it

Unless its as light and breathable as a set of cammies the troops wont wear it, the politicians will like anything though.

Something to keep in mind when designing gear for grunts: We strip the cardboard out MRE's to save room and wieght and generally choose/modify the rest of our gear with the same approach. Good luck to you.