Whatever, but there is something as performance which creates more importance to the characters, in that aspect, Shabir and Sriti have put in more than that is required for the serial. Their performance is something which binds other aspects together whether we want to accept it or not.
It is the writers who had created Tanu as a more important character just to keep Abhigaya separated. But if they had wanted, they could have focussed equally on Purab and Bulbul's character with Aalya in between. Many interesting plots could have been hatched along those lines and Raj, Purvi and Suresh too could have contributed to more interesting story line. But the writers chose just to give all that combined to Tanu and Aalya.
But looking at how much importance the writers have given to Tanu's character it is not as if it has been justified enough by Leena's acting. Most of the scenes have been created to keep her acting from being fully exposed. In that aspect, I feel Aalya deserves much more screen space.
But I want to reiterate one thing, Abhigaya has been beautifully portrayed by Tisha till now. Abhi and Pragya have become very popular. I feel the writers should give due importance to both Abhigaya and Tisha and allow them enough screen space on their own to fully blossom that relationship without Tanu's presence. That much is owed to them by the writers. They cannot allow their relationship to be marred by giving undue importance to Tanu. Let Tanu be in the serial but outside MM and in different setup.