While I dont Oppose some CleanUp in the Configs. Renaming stuff. I dont think that is a Wise Idea. That will lead to much more Confusion.
For example, if you were to Change Rarity or Size, I would probably still always call it the old way. Because I used it for something like 4-5 Years.
As for the Comments, some could be a bit Clearer, true. But on the "Size" and "Rarity" I dont really see much problems with that.
The Only thing I would change would add a Comment to each size setting which way is "Bigger".
Apart from that, Size, Rarity, and Frequency seem for me a nobrainer:
Size = How Big
Rarity = How Rare
Frequency = How Often