Changing the domain name to a keyword rich domain has a lot of pros and cons associated with it. I've listed some below:
Pros
- the obvious - you get the benefit of a keyword rich domain name and over time it can rank well for that keyword
- Easier to optimize for that key phrase
Downside
- Google has gotten very tough on over optimization and exact match domain names
- Slight over usage of the keyword on a page can result in a penalty
- You will lose all the traction that you site has gained with the generic brand name over the years especially the direct traffic that comes to the site
- You will have to 301 all the links to the new domain name and will lose rankings temporarily before google reindexes all the links.
As you can see , there are more disadvantages on changing up the domain . I would not change it up for a keyword rich domain. As opposed to that, try and get the generic domain ranked for that keyword by following all the best practices for SEO ( strong on site, off site, PR )