This was interesting, I first followed your scoring system and I got a pretty low score on Seasons and Cats & Dogs, so I gave it some more thought, Seasons doesn't have a world, but when you think about it. Seasons are all worlds with different weather, so it's the different weather effects that are transforming the world. Cats & Dogs gets more in CAS because of the many different pets that are available.
I ranked these packs based on how much I played them when they were released, if I remember spending time a lot in a world or built many houses with a certain pack for example then that pack gets ranked higher for me.
https://i.imgur.com/Khfqfft.png
The list to the left is how I would rank the packs without using your scoring system, the list to the right are the packs ranked after your scoring system.
I think this scoring system showcased pretty well how I might remember having more fun with certain packs and how different it can be when I am comparing the content in these packs with the content in other packs.