What I'm saying is that depends on the nature of the code that's being written. Many small improvements can be made with a simple code change that has clear meaning on its own -- a long approval process would just make these changes less likely to happen.

The point of having an approval process of any length or complexity is precisely to make changes less likely to happen ad hoc. That's a Good Thing (tm)!

Sometimes "small improvements" have ramifications outside of the context of the change (potentially significant ones). The person implementing these improvements has to understand the scope of the change (including side effects on external systems, if any), and that effort should be documented somewhere or at the very least reviewed by peers for correctness, especially for truly mission-critical or sensitive systems.

It doesn't have to be a "fill out these forms in triplicate and don't forget the new cover on your TPS report mmmkay" kind of documented effort: it's not one extreme or another.