.....I don't know how PHL will end up in the future...... CLT, PHX and PHL will no longer be what they once were because we now have hubs in prime locations. All this is my opinion. What will actually happen in the future? You never know in this crazy world of commercial aviation.
2 Weeks ago, AMR agreed to a new 5 + 2 (Option) year, $150M Lease at PHL. The Agreement includes funding for an additional major airport project to be determined over the next 18 months. Unless things have changed, CLT's current Lease does not expire until June 30, 2016 - but of course that could be re-negotiated. The supposid ongoing discussions between CLT and the Airline should provide pretty clear insight (if released) into what's in store for CLT's future.