This has become almost the perfect train for Uttara Kanara passengers ever since it stopped going to MAQ and permanently got diverted via Kunigal. If only more coaches could be accommodated without hampering the timings.

There'd be more seats available at 16586 from Murdeshwar and 17310 from Madgaon, but most people would rather go board a train from Talguppa railway station instead.
...
more...

Only meaningful alternative would be taking a connecting train with 16511/12 at Mangalore which would be slightly less time-consuming.

Wonder why there isn't similar demand like Panchaganga for 16515/16. It could be given a daily run and would help matters with getting additional infrastructure for KAWR.

It makes sense to have a look at revising the slot of 16585/86 or facilitating an RSA with Vasco Exp to find a more optimum schedule for it. As it stands, there is scope to slot in one more train between 16511/12 and Panchaganga.

16515/16 has the same 14 coaches as Panchaganga, and the difference of 3 hrs in runtime end-to-end is definitely not doing it justice. Certain stops upto Hassan could be reassigned to 11311/12.
...
more...

Currently a higher portion of travelers in 16515/16 come from Mangalore due to the reasons you've touched upon, but SR would not receive it at MAQ instead of MAJN (the Madgaon MEMU and SBHR Passenger have more privilege). If SWR expect more patronage from coastal Karnataka, the train should be speeded up and given a daily run bypassing Mangalore while an early morning Vande Bharat from Bangalore departing ahead of 16515 and returning behind 16516 would be a good deal for Mangalore.

And there is sill room for another non-premium daytime train. With 2 rakes, Gomteshwara can run daily taking the timings of 16540 and making a late night return to MAQ.

For these bypassing trains, Farangipet station should indeed be developed by SWR. In fact they could have operated Padil station like Thokur instead of handing it over to SR who have decommissioned it for detaining freight trains.

Return schedule would be a little hard to achieve realistically. It has 10 more halts than Swarna Jayanti (which departs at 14.15) between TVC and KPD which takes 15 hrs to reach KPD.

Scheduling Sabari 30-45 minutes ahead (ahead of Parasuram more importantly) might work, now that Venad Exp goes through ERN and there is no queuing behind. There is further scope for speeding up between CBE-KPD.
...
more...

People from TN do use the train to both Kerala and AP/TG.