There are a lot of good arguments in favor of throwing away your traditional test framework. The strongest I've seen, however, is that it helps make it easy to add tests.
A very talented development manager I used to work with would say, both to me in my testing capacity but also to his team: "If you want more tests, make it easy to add tests." Build tools to interact with your product. Code an interaction. Capture the output, and you have a new baseline test!
By focusing on tools to interact with what you need to ship, and not on writing test cases to match the language of a test framework, you make it easier to add tests.
Baseline tests facilitate test writing by not locking testers into a framework. Sometimes, Python is the best language to use; other times, it could be Ruby. The best tool could even be curl or a shell script. Not being attached to a framework means you can write tests however is most natural. This makes testing easier. Easier test writing leads to more tests.
Emphasize the tooling for interacting with your system under test, not your test framework.