Yes, that was a worst move to accept the UDAY Express in the first place. The 12677/78 was doing a lot better as dedicated train. Even during those days, there was a request for ONT. To your question, there is definitely a great scope for a regular SF or Express with All class configuration (SL, 3A, 2A, UR) doing better than UDAY. The concept of UDAY is just an eye wash. Its day train to ply in high density routes like MAS-SBC. It doesnt work in CBE - SBC route. Instead of UDAY, in the same slot if an Inter City Exp is deployed, it would make more. In the mentioned trains, though general quota, it has to be sharing with other destinations too. I wouldn want to take seats which belongs to CAN, ERS and other towns. When you have a load for a dedicated train from CBE, TUP, ED,...
more... why do you wanna compete with the other trains?? This actually does reduces the load on KL bound trains.