I think breadcrumbs are important usability feature - and using decent keywords can be important for the visitor, too. If the page has a lot of content, I'd just lower the keyword count in that content, going to more pronouns and synonyms.
I agree with Tedster. No way would I remove breadcrumbs for a reason like that. I did however experiment with going from absolute to relative links. That alone improved my density a percentage point on some pages.
If you want to give up usability for your customers/users, it might have some tiny effect. I think it is a pretty silly idea actually. I never heard of any of the search engines applying any penalty for breadcrumbs.