Everyone has some opinion. There are the people that say that flakes do to much and others are saying they do to little. No matter in which direction you go, someone is always unhappy.
Eval caching depends on pure eval and pure eval was previously not possible because channels are by design the most impure and cursed thing and are just a bandaid that lasted way to long.
The scaling with big repos gets worse as some use flakes instead of their normal build system which is not the intended use case. You still do development like normal with the normal build system.
Flakes are still unstable because everyone wants something different and there are still breaking changes planned which then everyone would wine about and maintaining backwards compatibility is a pain if you still change fundamental things.
Eval caching depends on pure eval and pure eval was previously not possible because channels are by design the most impure and cursed thing and are just a bandaid that lasted way to long.
The scaling with big repos gets worse as some use flakes instead of their normal build system which is not the intended use case. You still do development like normal with the normal build system.
Flakes are still unstable because everyone wants something different and there are still breaking changes planned which then everyone would wine about and maintaining backwards compatibility is a pain if you still change fundamental things.