TRPs do matter even in finite series. The channel still needs profits out of the show so they have to deliver on the numbers front like any other show. Now the issue is that if they don't deliver, they're taken off prematurely and if they do, they're extended and ruined like any other regular show.
And yes, if EDT story turns out like what you mentioned, it would be very disappointing. Although I doubt they've changed the script. When Namik posted from Manali shoot, he said this was always planned - this was to calm his fans down who were upset because his character wasn't getting enough to do.
Although it is a different story that I don't see him doing much now either. At least without dialogues, etc. Shiv was mysterious and intriguing. It's very hard to believe that after playing a character as layered as Shravan, he was so excited for someone as seemingly bland as Shiv. It doesn't matter if it's a ghost, it's done nothing for him as an actor. Hoping beyond hope that this changes in the coming episodes.