When creating a project like that it’s important to inscribe it in the existing literature. Why was the library created? What are the alternatives?
One thing I cannot live without anymore is having the ability to build a log context, for example attach the current request’s user ID is invaluable. It promotes consistent and easy to debug log messages which is really hard to achieve without that. https://github.com/sirupsen/logrus is a decent logging library that supports this.
I guess for CLI application, it’s more important to have nice colors and that could be a nice niche for OP’s logging library.
If you want to see where we ended up with our logger: https://github.com/blend/go-sdk/tree/master/logger
A couple key considerations there; log messages are “events” that are strongly typed, and get sent through an event bus so you can attach listeners to them; this is useful for collecting errors and writing request stats etc. by hooking into existing logging.