And all the stuff you did mention has been done before. Bridge sections have been added to blues forms, there usually the same though, dominants back-cycling in 4ths, or some type of ii v variation. Added measures at the end of the form, this is usually done by playing 2 turnarounds back to back, there's many variations but this is a common one: 1 6 2 5 1 4 1 5 .
Blues is such a simple form that there is only so many alterations you can do to it before you start to blur the boundaries.