Currently, there are elections in five states and BJP is not a big factor anywhere except Assam. So these elections need not be taken as a referendum on Modi or BJP central leadership.  Nobody would reasonably even dream of BJP getting power in West Bengal, Kerala, Tamilnadu and Pudducherry. So, the discussion of Modi's performance is not so relevant. 

Public opinion always matters in a democratic set up probably not for one family party and such other communal and anti secular forces , who work solely based on corrupt practices, let us leave that aside because for today's government it does not matter, what really matters is  its own overall performance and how well it has been received by the people ...

BJP leaders are realists and know the reality much better than opposition or the communalists who think they are experts in everything after having messed up with the nation.. Any small gain is a gain for BJP because it is making its presence felt in these states which is good enough for now..

well if we speak about BJP then we all know that there is no other famous leader at present who comes on the expectation of the people instead of Modi and i think just because people of India believe in Modi, the BJP are getting enough importance in the country