First of all, SNA, DCA, and JFK and I am pretty sure LGB as well ARE SLOT CONTROLLED... not facility constrained. There is a difference in that with a slot controlled airport - whether in the US or in other airports around the world - there is a process for carriers to request access. SNA for one participates in a slot conference.
Even at the slot controlled airports, the DOT and DOJ have forced open access or created slots... and it isn't behind the realm of possibility that could happen again.
BUT slot controlled is not facility constrained. DAL is NOT a slot controlled airport. It is facility constrained, just like CLT and other airports that have a single carrier that control a high percentage of gates. CLT IS REQUIRED to have a plan to provide access to other carriers who want to serve the airport.
DAL will either have to come up with a plan that provides access to carriers that cannot serve it, become slot controlled (which I can assure you that WN doesn't want) esp. since slot controls provide a mechanism for access, exchange, and trade, or DAL runs the risk of losing federal funds.
US airports cannot permanently block access to new entrant carriers.
The entire Wright Amendment itself and its revisions will be challenged if WN and other carriers are even remotely successful at DAL. There is no other airport pair in the US like DAL and DFW where two carriers are precluded from serving one airport including at risk of losing access at the other.
Factor in that 2 airlines and government officials carved up access to the airports to the exclusion of other carriers and the ability for the free market to function is highly limited. There is no basis for private companies to be able to squat and carve up a market to the exclusion of competitors, including each other.
If Wright isn't challenged now and if access doesn't change, it will be challenged in time, esp. if WN is even half as successful as I think they will be... and they want to be.
There is no basis for excluding other carriers including prohibiting WN from serving DFW unless they lose gates at DAL.
The DOJ's sole logic is to provide WN with an opportunity to grow its presence from DAL w/o the threat of AA squashing them. It will become obvious before very long that WN doesn't need any protection and that the exclusion of other carriers including WN and AA from each other's airports - is contrary to the public good and legally without defense.