I would agree...
And exactly for the scenes you mentioned... there is still some spark left.
And in the current storyline replacing NB wont work as far I understand.... because the story is set around CN, V's vaada to KJ and all that happened post that...
Replacing NB would mean a complete overhaul of story and Sai's solo journey or a new lead with her... But because she is an orphan and there are no non Chavan relationships for her... Even Pulkit is related to Chavans... the show will have to end. It would be a completely different story... more like a spinoff.
The only solution at the moment is to take time, work on the story and stop advance telecast. Its a practical problem and nothing else. I don't think there will be massive improvement but yes at least the writing can improve and so can the use of BDs. Shooting an episode in 2 days time is anyway better than doing the same in few hours and overworking the entire team. They have been doing this for months... its a blessing no one has fallen ill.
As far as the personal equations are concerned... nobody would bat an eyelid if it doesn't reflect on screen. If onscreen improves, it wont matter who is chummy with whom. šš¼
Most importantly though, leads are supposed to suffer in all ITV shows... but there is some payback for the negative characters in the long run and there are some happy moments in between the tracks. If Ghum makers include these two aspects, the show will survive and do good.