Low TRP of the show has more to do with programming issues of Colors since they don't air shows on time rather than any actor. Ever since October end, the timings of the shows have been delayed by 10, 15 & 20 minutes. Last week itself, Silsila was airing on 11:20-11:50 slot.
As per Salil who posts TRPs, TRP is counted for time slots.
At this point, no one can tell real TRP of any show since none of the shows after 10 are airing on time for 4 weeks.
So, no actor can be blamed right now for low TRP as it's programming issue playing with TRP of every show airing on Colors after 10.
Besides shows after 11 enjoy more of online viewership rather than TV viewership because of timing issues.
I hope it made some sense regarding TRP thing. To be very frank, no one knows how this TRP thing works for a particular show, especially when shows don't air on time.