i dont think you should expect a huge improvement on burn in ..universally speaking.
if your expectations are very high , you might fall flat on the face, if it does not improve much and you might hate it as well.
I was not expecting much with my S4, but they did improve with burn in , the treble smoothed a bit. but if i would have been expecting it to improve..I would have wanted the mids better , treble better
...and (you can guess)
The K702 on the other hand are improving every day, i think i have done ...1.5K-2K hours on them they still are improving..!
if your expectations are very high , you might fall flat on the face, if it does not improve much and you might hate it as well.
I was not expecting much with my S4, but they did improve with burn in , the treble smoothed a bit. but if i would have been expecting it to improve..I would have wanted the mids better , treble better

The K702 on the other hand are improving every day, i think i have done ...1.5K-2K hours on them they still are improving..!