In SEO a surprising number of people get a little too caught up in what they are doing. It is astonishing just how many SEO writers actually forget that they are writing for people. People do read SEO content and if you get too focused on the robots, then you are likely to lose out on leads. There is nothing worse than reading an article that is written entirely for robots. It is obvious and it reads terribly, it is a very quick way to turn people away from your site.
While your site does have to be geared towards robots, it is possible to do so without turning away human customers. A smattering of keywords is all that is required. Seriously, once or twice per paragraph is enough. I have seen some sites that come closer to once or twice per sentence.
Do not spend too much time worrying about keyword density, it is not the be all and end all as some would claim. As long as your keywords appear throughout your content, robots will index it. Getting too scientific about keyword density makes content production take longer than is necessary. Keep it simple, replace unnecessary pronouns with keywords if you feel that you need to boost the density a little bit, play it by ear.
If you are concerned about the robot / human balance of your material, you can always contact us at Brick Marketing. We have a great deal of experience at producing high quality SEO content.