Context
Romans 3:23 should be read within the flow of its chapter and the larger argument of Romans.
Common Interpretations
Every person stands in that sentence. The problem is not that some people need a little improvement while others need a lot. The problem is sin, and all have sinned. Sin earns death. Eternal life is not earned at all. It is given. That is why the gospel is good news and not advice.
Current Position
No defined position is stated here yet beyond the common interpretations above. As related study develops, this section will be updated where the text warrants a clearer conclusion.