for Philip, my view for what it is wortg is that with all kit you need to have the standard issues...
weight
protection
fit
maneuverability
with a thigh pad the fit is key and you don't want them move when you run between the wickets or to be constantly rearranging them when you are about to fave the ball.
protection is also a given.
with the original p1's I found them quite bulky, but as far as I am aware they are better now.
none of that is rocket science.
having them last is possible another issue with most thigh pads, but the aero ones are ok too.
if you could improve the protection while making the padding thinner you would be onto a winner...