I believe you were inspired by Shoji Kawamori on this one. the only thing wrong with the leg is the left one, the knee bends at an awkward angle, its not too spindly. As for balance the backpack is rather large, so two options are open to this design, longer "heels" that support the weight on the back better, or a smaller backpack. Good design thought ^^
Thanks! this is one of many development sketches I do. And most of those I do with a ballpoint pen so I have learned to except the mistakes I make when drawing them. I've also learned to better visualize what I'm trying to draw before I draw it. That saves time when I go to make a final drawing.
I have just finished a small, space combat mecha in Lego (only virtual Lego tho, not RL ones ). I think the next one is going to be something like this here (hunched forward torso and a heavy weapons pack in the back).