The fabled Terminal 6 would most likely be the new Western Terminal Building we've heard so much about -- while the city has no current plans to build one, the Elgin-O'Hare West Bypass would more than likely spur such a development to take place sometime in the future.
As for T2...I would be in support of a complete reconstruction of it, but that would be detrimental to the operation of the airfield unless they had additional gates to handle those lost for the rebuild (i.e. if T6 were already in place). Could you imagine shuttering 38 gates across two concourses for a minimum of 2-3 years at one of the busiest airports in the world with no gates to use in the interim? That'd be a logistical nightmare. Rather, I'm more in favor of what denizen mentioned above: a phased rebuild/possible expansion of facilities with the footprint they already have. As mentioned, the only existing facilities that have enough space to warrant additional gates would either be T3 or T5.
Either way, T2 desperately needs a facelift; while waiting for a flight in June, I had to explain to a couple from Austin that they'd stumbled upon the "ugliest terminal at O'Hare". It was undoubtedly impressive in 1963, but today...
