Yes, It's really sad to see It has been slowed down between Jhansi-Nizamuddin.
I personally believe the timings of Uttar Pradesh Sampark Kranti Express should be revised from NZM. Begining it's journey from NZM 2330 JHS 0530 MKP 1200, and return at MKP1730 JHS 2330 NZM 0530.
Shifting 12448 to slot of 2330, will provide him better prestige, regain lost punctuality and preference and also avoid clashes with SBC Rajdhani and Andra Pradesh Express.