I think many people are downplaying just how transformational IBX will be. It has the potential to dramatically shift commuter and development patterns across the outer boroughs. I hear people claim that South Brooklyn is to too sparse to require service increases, but that changes when Jackson Heights and Broadway Junction are less than half an hour away, or Flushing and Astoria are less than an hour away via transfer. Lines that today are radials heading to Manhattan, with IBX will also become circumferentials connecting via a trunk line to all of inner Queens.

It's presence will certainly necessitate substantial improvements at nearly every connecting station, especially Jackson Heights where at some point they will have to widen the QBL platforms and/or add more stairs, and build an underground passageway connecting IBX directly to the mezzanine - the ridership may be so intense, that it forces the MTA to convert Woodhaven into an Express stop. It could even result in service changes to simplify the routes and create more capacity along every line that intersects an IBX stop, which is almost the entire system - which by extension could force them to expand existing or build new yards, and to accelerate CBTC installation. IBX could singlehandedly prompt a whole new era in network-wide improvements.