Stars are planned.
I have implemented having normal names for the number formatting (as well as scientific), however that will become available once I add settings and add in all of the names.
I went with A B C because it was far easier to generate for huge numbers, and once I know what kind of number range I'm going to I can set up the names.
A B C is fairly standard for idle games, it's only really AdVenture Capitalist that uses full names. It's harder to reason with, whereas with letters you know that P is 1000x more than O.