> Usually there are several other possibly-non-obvious improvements the tester is looking for. Whether these improvements are obvious to you or not is a sign of experience.

There is a risk here for something that even really strong intermediate programmers fall into where they take a very prescriptive approach to programming so they tend to not understand things built from first principles and also tend to overvalue things like future-proofing and abstraction. Since you don't mention any specifics it's easy for people to fill in the blanks here and assume that at least a good portion of the things you refer to are those kinds of things.