Feature:
Consistency+ makes it possible to use a stonecutter to make stone from cobblestone. I don't think this should be possible since vanilla Minecraft requires you to smelt cobblestone to make stone. Instead, I think you should only be able to craft the cobblestone variants when cutting cobblestone.

Config would definitely be the best option. I personally find the vanilla stonecutter to be utterly useless and even with C+ making it significantly better, it's still not all that great beyond early game. The way I see it: crafting is crude and as such requires 4:1 ratio in order to transform cobbled variants into normal ones; smelting is logical and is the next step to crafting, outputs at 1:1 ratio, can be automated, but is slow and requires fuel; stonecutting at this point becomes very useful because it requires no fuel and outputs at 1:1 ratio, however, it has to be done manually and only 1 stack at a time. So in the end, once you automate your smelting, stonecutter just becomes a nice thing to have nearby just in case, but definitely not overpowered.

mods like create make it possible to automate stonecutter recipes, so some way to balance it with a config is appreciated
edit: I just noticed this doesn't add a recipe, so create can't see that it can craft this 🤔

This feature was added as an early game quality of life improvement, however I do agree that it is a bit overpowered compared to the other methods of un-cobbling stone. Vanilla's is slow and requires fuel, and the crafting grid method (also added by C+) is fast and fuel-less, but outputs 1 for every 4 cobble. Stonecutting simply requires that you have 3 stone and 1 iron.

I would like to keep this feature in the mod because it makes the early game in survival a lot less tedious, but once you have a stonecutter (generally pretty early on if you build a lot) it removes any benefits of using the other two methods and is a bit powerful.

A potential solution to this would be to increase the amount of cobble needed to cut a full block (possibly 4 to match that of the crafting recipe). This solution would bump it to be less powerful than the crafting grid recipe, as it would allow for 16 cobble to be crafted per stack, but only in bulks of 16 compared to the 64 that can be made by utilizing all 4 crafting grid squares required by the recipe.

I'm not sure if there are other configurable features in this mod (I don't see a generated config file), but a common practice for non-vanilla features is to add a config value to toggle the feature on/off. :)

We have had plans for a config (and adding this feature to it) for quite some time, however currently we don't know when we'll get to adding it.

Config would definitely be the best option. I personally find the vanilla stonecutter to be utterly useless and even with C+ making it significantly better, it's still not all that great beyond early game. The way I see it: crafting is crude and as such requires 4:1 ratio in order to transform cobbled variants into normal ones; smelting is logical and is the next step to crafting, outputs at 1:1 ratio, can be automated, but is slow and requires fuel; stonecutting at this point becomes very useful because it requires no fuel and outputs at 1:1 ratio, however, it has to be done manually and only 1 stack at a time. So in the end, once you automate your smelting, stonecutter just becomes a nice thing to have nearby just in case, but definitely not overpowered.