Rather than a Duronto halt, railways can run a weekly JBP-SRC Humsafar (via G) in addition to the current one stopping at only major stations, travel time here will more or less be the same.
w.r.t Mumbai - JBP already has many trains (including a Duronto).
For Pune - regularising the current JBP-PUNE Festival Special with some increase in frequency will...
more... be a good idea.
For divisional HQ, I think it's well placed and provides a better collaboration with CR, so shouldn't be moved.