I think this will increase the volatility in the market. But of cause weight of the share in the index also important. During recent past market was manipulated using so called Good Shares such as JKH, CARS, SLT, BUKI, NEST, CTC, etc. Weight of the popular shares are less significant comparing to high cap shares. But as these shares are mostly trade in the same pattern as a group they can give direction to the market. UP or DOWN.
I think now market will show real sentiments quickly. But on the other hand manipulators will have better more options.