Rand has the issue of platform support for securely seeding a secure rng, and having just an unsecure rng might cause people to use it when they really shouldn't. And serde is near-universal but has some very vocal opponents because it's such a heavy library. I have however often wished that num_traits would be in the stdlib, it really feels like something that belongs in there.
The std has stability promises, so it's prudent to not add things prematurely.
Go has the official "flag" package as part of the stdlib, and it's so absolutely terrible that everyone uses pflag, cobra, or urfave/cli instead.
Go's stdlib is a wonderful example of why you shouldn't add things willy-nilly to the stdlib since it's full of weird warts and things you simply shouldn't use.
This is just social media speak for inconvenient in some cases. I have used flag package in lot of applications. It gets job done and I have had no problem with it.
> since it's full of weird warts and things you simply shouldn't use.
The only software that does not have problem is thats not written yet. This is the standard one should follow then.
Too big for many cases, there is also a lot of discussion around whether to use clap, or something smaller.
