Writing documentation and fixing bugs is in fact not the bar for a senior software engineer. I don't disagree with the promotion committee on that front. IIRC, Senior Software Engineer is a terminal level. You aren't expected to advance any more once you reach that level. Some do, but you can stay a Senior Engineer for the rest of your career and that's fine. So certainly "can fix bugs and write docs and tests" isn't…
> Writing documentation and fixing bugs is in fact not the bar for a senior software engineer. The bar for a senior engineer should be identifying the biggest problems plaguing an organization, and successfully tackling them. In some cases, the biggest problem is building and launching something shiny and impressive. In other cases, the biggest problem is fixing bugs. Refactoring complex/unstable systems to make them…
You're missing the crucial step of advocating for these problems to be solved. Until you know this is actually something important to the organization, you're just scratching your own itch.
In OPs example, did it really matter that the data was occasionally bad? Quite often analytics exist to check a box in a sales pitch, but nobody actually looks at them. OP couldn't quantify this impact for the promotion committee because they likely didn't quantify it for anyone but themselves.