I think I am going to have to agree here. The staff was a good choice for an engineer's weapon of sorts. Also Matoran are known for being a little stockier by design so having a lanky and thin Matoran may not go over as well. I don't think you can make him any shorter, so expanding his shoulders to widen his profile may be your next best bet. It was the weapon that inspired me to go with Nuparu in the first place - up until I found that part all I knew was that I wanted to make a matoran using the torso build. I probably should have gone with a shoulder build closer to the protector of earth, but I wanted to push to see how small of a torso I could make. The claw is there as a sort of roll cage around the visible gear pattern on the top of the torso to go with the power-miners-inspired aesthetic.