However, I'm thinking that, just in the future -- the Better Spawner could maybe be thrown into a series of .json files as opposed to one gigantic .json?
Essentially a .json for blocks, one for biomes, etc.
This is to make adding compatibility files easier, such as if someone wanted to add support for Better Nether without erasing someone else's Better End support, and, if you can get into it, there's even a way to make any compatibility data pack NOT replace the original one. Farmer's Delight does that fairly well, and I'm sure there's a few other mods that do it too but looking through that gave me this idea.
tl;dr: A way to make the Better Spawner config more of a plug-and-play thing.