This is precisely what Express has been looking into for the past 18 or so months - moving volume over to Ground for delivery and only have Express deliver overnight voilume. There are a few reasons why they haven't pulled the trigger yet, the poor performance of Ground is the primary reason at this stage. Express doesn't want to alienate their customers with Ground service levels and issues. The second is the continued hope/belief that the lobbying campaign will keep Express under RLA. Your speculation is more than just speculation, it is actually right on the money as far as what the planners in Memphis are looking into.
The lobbying campaign to keep Express under the RLA has cost Express about 5 million for all of 2009. Some other thread has a link to an article for the last few months of last year which states about half that amount. The total for all of 2009 is just over 5 million. The brown bailout propaganda is part of that expense, along with lobbying fees and other public disinformation attempts - as this forum has been subjected to by various Express shills.
The latest "Doomsday" plan in Memphis should Express lose its RLA status is to attempt to go to a series of local "independent service providers". Think how DHL performed their delivery operations in the US - and how sucessful that was. They know they can't pull off the IC scam, but they want to frame it so that there is a series of separate companies (regionally based or even state by state), that are not "linked" under a common umbrella. Each "independent service provider" would be organized as a separate company, but majority owned and managed by Memphis. This would enable Memphis to maintain absolute control, but the employees of these localized companies WOULDN'T be Express employees - they'd be employees of the service provider. This would prevent nationwide unionization of the DGO workforce and if a service provider were to experience unionization, Express (that is the local service provider acting under instructions from Memphis) could play hardball, perform a lockout and hire a new workforce. These are tactics from almost 100 years ago, but they were effective then and can be again given the current work environment.
Under this scenario, the only thing of Express that would remain "Express" would be the current AGFS division. DGO would be devolved into the local service provider scheme. AGFS would easily be defended as needing to maintain classification under RLA rules, since it deals with the long distance movement of volume and is primarily focused on aircraft as a method of performing that movement. This is truly a Doomsday scenario for Express, since practically all of DGO - with virtually all salaried employees, managers and all - would be spun off into the local service providers. The salaried employees would be none too pleased, since their career prospects would be shot in the rear by this move. This is why it is still in the planning stages and not being discussed even "internally" - only leaks are getting out. It isn't just the Couriers that Express wants to "sell down the river", they're willing to sell out their true "FedEx-ers" (DGO managers) if they feel it would serve the need of FedEx Corporation. Most managers aren't too pleased with the prospect of being turned into something resembling the manager of a local FedEx Office - with the compensation that accompanies that job. So while this issue is primarily focused at the Couriers/RTDs/Mechanics, it will end up sweeping up the salaried employees in DGO with it should Express lose its RLA status. I haven't heard of any "threats" against DGO managers yet - regarding keeping their employees non-union - but if the RLA status should be lost, FedEx Corporation won't wait for a unionization vote.
So the pulling of Express' RLA status would be a Pyrrhic victory for the wage work force. It would be a victory, but it would result in Express dissolving DGO - thus making the change of labor classification meaningless. FedEx knows that if they permit unionization, Express will no longer be cost competitive with UPS and Express would rapidly lose domestic overnight volume due to the increases in labor costs. Express could become competitive, but it would mean massive restructuring of its management and support structure - along with pay cuts for the bloated staffs present in Memphis and the regional district offices.