I think that you need to step back and look at the bigger picture. There is no one magical solution but there are a lot of things you can do to improve results and improving quality is definitely one of them. How much thin is too much? It's probably relevant to the other pages on that primary topic from other sources, how does yours stack up?
In SEO when you overdo any one thing something else begins bulging out the other side as a result, everything in moderation!