Anti-Penguin Strategy?

I have an 8 year old domain with a generic "fishing" name. I had optimized it's home page and some other pages for a fishing subniche. The home page and those related sub pages got slammed by penguin for over optimized backlinks. There are too many to try to dilute.

I want to keep working with the domain since there are other traffic sources sending traffic to it.

Other pages on the site for other fishing subniches are still doing well.

Here's my question about penguin:

What if I change the home page to another fishing subniche, add new and related subpages for that new subniche, and then begin backlinking the home page and the other related pages (correctly) for that new subniche?

If I change the keywords totally and begin the off-page SEO for the home page from scratch for the new keyword, will it be much the same as if I were beginning a new domain with that keyword?

Or is the fact that penguin slammed the home page already for another keyword going to hurt the new keyword's chances too?

Does penguin just affect that keyword that was over-optimized for or is the specific URL trashed for anything new I might want to promote on it (with completely new content, etc.)

Thanks for your input!