Quote from earlybirdstango:
i think as all trading strategies, there will be some adjusting, but if they can take all the arca's volume and put it infront of the tape readers that follow the NYSE, it can show a lot more depth to the story.
Also, now that NYSE is a for profit public company, they will do their best to increase volume, reduce fees, and promote market consistency.
There are already talks of opening the exchange 30 minutes earlier to get that early morning premarket volume during trading hours on the NYSE. Seems like they are doing their best to keep things as they are, and if anything, make it better for their clients/traders.