People giving it a lower rating might be the ones who are used to gripping tales these days from the very first episode as gone are the days of good slow burn soap operas.
To really appreciate this, one needs to be familiar with Vikram Seth's writing, which itself takes time to dwell in you with its fine details to all the characters and the period they are set in and secondly, not many people are familiar with Mira Nair's work. She has a beautiful eye for details in her direction and the way she narrates her story is always with a kind of tenderness and her characters take their own time to amalgamate.
I understand, at first, it's a bit unusual to see many familiar faces having lengthy conversations in english, especially the actors whom we have only seen in 'Hindi' speaking cinema/series till now. But I do believe the ensemble is doing justice to their roles and with time we will become more attached to them. I for one will be rooting for the show.