The only problem is everyone knows how this is going to end up, to include (much to their chagrin) American's management.
American will go in and throw some flights out of Love Field to KC and St Louis. They will carry some passengers. Not as many as WN but some.
The market will get bigger between Dallas and those two cities because prices will be lower.
Southwest will make money carrying passengers at those fares but American won't.
To add insult to injury in this go-round, Southwest can feed connecting traffic from SAT, AUS, LBB, MAF, and ELP thru Love Field on to the two Missouri cities.
Over at Love Field AA won't have that luxury.....and unless they are flying RJs, they won't be able to sell DAL passengers on a connection to LGA, ORD, DCA or some place like that.
If they do go ahead and throw RJs on the route, they can do the connection bit, but they will be throwing most of the O&D traffic away. AAdvantage miles or not, a 737 is a much easier plane ride to sell than the Barbie dream jet.
Having American at Love Field is not going to sway many of Southwest's loyal following....and they (AA) will be pulling some of their DFW traffic over to "the other airport". Once there, some of the AA folks might <<<horrors>>> give WN a try.
For American this is a lose-lose proposition, and had I been the guy in charge, I think I would have pursued the less risky path. Specifically, I would have stayed at DFW, allowed Southwest's fares to generate a larger market for both of us, and grabbed the passengers for whom DFW is more convenient. I would have sweetened the pot with some extra miles and promotions. I would have had all my connecting traffic feed and probably would not significantly miss whatever traffic WN siphoned off. The only thing I would have missed is the revenue lost by the lower fares, but that happens whether I am at DFW or at both Love & DFW. The advantage to staying at DFW is I do not incur the costs of opening up and staffing a new station.
Since they have announced their intent to move some flights to Love Field, I reckon they stay there awhile, get their butts kicked, declare victory, and move everything back to DFW.