PIT is an amazing facility, the people are great, and until recently the airline had alot of support from the public and the city there (especially compared to PHL). But it is the weakest link. It is better located geographically than PHL, which is too eastward- no one wants to have to go east to go west. Its nicely situated to be a great omnidirectional hub connecting the northeast with the south, the east with the midwest. PHL and CLT are too far east and south for some of PIT's more midwestern markets. It looks like it should be a great hub, and it probably could be if US didnt have so many redundant operations nearby. The O&D traffic is dreadful and it serves pretty much exactly the same places as PHL with a few exceptions. For the most part it doesnt bring much to the table destination wise (West Virginia I guess, and a few places in Indiana and Ohio), its more its location thats vital. If only you could get a crane and lift up the airport and move it a few states west.
CLT is a great hub. Its O&D is not terrific either, but its location and facility are great. It brings alot more variety to the route structure with comprehensive service throughout the southeast, while still serving alot of northeast cities. Theres also room for expansion.
I've often wondered if US could work without PIT (not that it is working now). PHL would have to pick up some of those cities and capacity, but cant handle it to large extent and isnt a great connecting point aside from north-south. So CLT would have to become a much bigger hub, with flights much deeper into the midwest and towards the southwest. US could essentially serve the same network, but with fewer, larger aircraft (e.g rather than 3 RJs from somewhere to PIT, CLT, PHL, an E170 to CLT and PHL) They could also increase connectivity in the three focus cities, strengthen the two remaining hubs to support more service, and redeploy mainline aircraft to more island, western, and international service (again suported by stronger hubs with more connections rather than three weak, redundant ones).
Any thoughts? I'm not bashing PIT or saying it should close, I'm merely trying to picture what a reconstructed route network would look like.