My opinion- What if NDLS-LKO AC superfast Extended to Varanasi by changing its catagory to Rajdhani with a slight speedup which is perfectly possible.
(If required add 2 extra coach as a compensation for Lucknow people)
This will serve 2 purpose Varanasi will get rajdhani & Patna rajdhani ki legacy maintain rahegi as discussions being going on for route change.