Nanny, I think it would help if you would define to us what your definition of Yeshivish is, because you see how everyone is answering based on where they come from. To people who are more modern, BJJ is as far right as you can get. To other people, it may seem less extreme than other seminaries. It depends where you are coming from. So if you want an answer that will help you, you should let us know more about where YOU are coming from, and your definition of yeshivish.
Hatzlacha.