Bluecat and his team got better over time with everything and fixed up a lot of Week 1 in the first place, what you're seeing are some hard limitations of what the creator is capable of, but in some aspects yes the animations will get better as you go, but the graphics stay the same and are honestly amazing. Though it may also be a comparative effect because of just how terrible other programmers at with posing/movement/and design.
Most of the size comes from not understanding how to properly manage the data sizes before, they've since learned better ways nya nya