Agree, I have already proposed this to IR via tweet a long time ago, but who cares.
Shatabdi's TT can be easily cut down to 8 hour 10-15 minutes even without using Push-Pull. A few days back it has covered BPL-NDLS in 7 hour 40 minutes with a WAP 4 which is not allowed to go beyond 140 kmph. By using Push-Pull P5 locos the TT can be easily made to a close 8 hour 5 minutes. Which would be very beneficial for the train as well as the passengers.