I was talking about 'main navigation' (used on every page) and it used to be using the keyword(s) repeatedly in that text was a good way to 'communicate' with search engines what the target page is about, but Google's openly stated (somewhere, I don't remember where off the top of my head) that's no longer a 'best practice'.
Basically, things have changed from 'help Google (and other search engines) figure it out any way you can' to 'do what makes the most sense for visitors and let Google figure it out'.
If you look at the nav. here it's a great example of 'what to do'.
Your ranking drop might not even be 'link related', but if there's not a 'solid set of links' coming in, it could be ... I'm not sure blog posts are really the answer though, some of it depends on the blogs I'm sure, but I would have serious questions about the strength and quality of the links you have coming in personally.