I have broken a few in car doors and what not and usually there is a fine line between regaining a slightly beefier rod that you can lay into the cast a bit more and a broomstick that is useless and horrid to use.
I find if it can be done; a rod with a strong butt end can usually be converted as the bottom end of the rod is initially built for the extreme work and will hold up when laying your arm into it, but you can still end up with a broomstick if too much comes off the top.
A rod built for casting and cut down to a bottom basher will still most likely have the casting rod bottom end and not be overly strong in the grunt department because it was never made strong in the bottom end of the rod.
I see your point, I have just repeated it...
oh well
Cheers