tedster - 3:37 am on Oct 19, 2012 (gmt 0)
From everything you've described I'd say yes - this all sounds like over-optimization to me.
I doubt that just changing bold text to plain text would make much difference on its own. And don't worry about some keyword density percentage, either. Just make it read naturally and let go of any search for "the formula". SEO is more and more of an art, rather than a science.