For reference as these were not in the OP.
In general I am very favorable to the design, my preference was always going to be the light frame. I do have 2 concerns. The first being the same concern i had with the original medium frame, the feet are really narrow. The weight needs better distribution. I would model the light frame feet to be similar to the medium feet, if on a smaller scale.
The second issue I have is perhaps a bit more problematic. Melee requires mass and force, the less mass you have the less force you can apply. Additionally the more massive the object you are hitting is compared to you, the more YOU are going to be staggered by the attack.
So...why are we putting giant melee fists on the smallest least massive frame? I feel personally that the hands of the light frame should be the same size as the medium frame, so that the weapons both frames can handle don't need to be different. But the above version of the light frame is seriously top heavy and unbalanced as is. The original artwork on the left (above) has much smaller omni-hands than the second render (right).
Nevermind the fact that I would prefer not to see melee focus as an aspect of the light frame in the first place, I still feel the hands should be smaller than the render on the right. Standard Newtonian physics simply does not support the render design.
EDIT: I had to submit my post earlier as I ran out of time, finishing now.
One thing I do like is the shoulder design, though the shared picture was really small resolution so I could not make out a lot of detail. It looks like the jumpjets are a bit more integrated into the frame which I really like. I also like the "pauldron's". Grummz stated that the tiny wings are intended to expand via forcefields when active, which is something I suggested for the medium frame, again 100% like.
I also approve of the assless chap design, I think that is a pretty awesome nod to the playerbase. And while I think that the fists in the above model are too big, I do like their design. I am wondering if a piston or two somewhere at the joint might be cool to have.
Personally I really like the fact that the light frame is so different from the medium frame. Originally it sounded like the light frame would simply be a skinnier medium frame. But this makes me think that perhaps the playstyle of the two frames could be made very different and so provide a good reason to use all the frames. If we can have a significant variation in the frame design, I am hoping that rather than making a lot of abilities exclusive to one frame I am hoping that we can use a lot of ability variants to add flavor enhancement to the frames instead of outright exclusivity.
One question I do have is concerning the sensor unit. In the medium frame it is a separate "head" that sits above the player. On the light frame is it intended to be more of a helmet? In the initial drawing there is no helmet so I am uncertain whether this is flavor in the render or whether you are going to have all light frames have a helmet.