I am not sure if the timings between SC<->SBC will clash with some other train, but, extension to MYS can be done only if doubling of SBC<->MYS stretch is fully completed/commissioned. The TT of other trains to MYS should also be changed accordingly else the suggested timings is almost on par with Mayiladuthurai Express.
I am also not sure of the patronage it will get between SBC<->MYS. It might get some patronage if CC charges apply between SBC<->MYS with stops at KGI & MYA so that some of the passengers who opt for KSRTC Airavat may switch to this one.The run time between SBC-MYS must be 2-2hrs 15min, almost on par with Shatabdi.