By default, the weightage is linked to the performance of the stocks in the sector. Historically, the weightage of financial sector stocks were around 30% but due to over valuation, it increased to around 36%. Secondly, the weightage will change if there is any addition or deletion of stock from Nifty like Yes bank moved out.
In my opinion, Fair value of financial sector in Nifty 50 should be around 30%. I don’t foresee any sectoral shift besides these 2 factors.