Did some homework, and apparently FFDOs do not actually have "statutory powers of arrest," making LEOSA a definite moot point.
Apparently FFDOs are only licensed to carry the firearm issued by DHS (a .40cal H&K) on flights which they are a crewmember. Furthermore, they FFDO must load/unload the weapon on the flightdeck where he/she is "on duty," thus the firearms must be unloaded for transport to the flightdeck.
In fact, one FFDO agent was arrested in NYC (go figure!) because he accidentally let his FFDO credentials lapse by a month and thus his standard issue firearm was "illegally in his possession". He was hauled off my NY Port Authority.
As not only a pilot, but a pro-2A citizen who is competent with handguns, it's plain stupid to have the FFDOs loading the firearms on the flightdeck; there's more important pre-flight and pre-takeoff procedures to focus on. They are deputized and obviously mentally competent, as such they should be able to carry as DHS Flight Marshal federal agents.
In this research I've found the program is actually wildly successful in the number of flights they cover. Currently, 1 in 10 crew members are FFDOs; conversely less than 1% of the flights are covered by Flight Marshals. With the FFDO program only costing an average of $15 per flight versus $3000 per flight in comparison to the Flight Marshall program, it's an obvious pragmatic approach to counter-terrorism.
Of course Obama tried to abolish the program as part of the FY 2014 budget...
http://www.redstate.com/brian_d/2012/02/15/president-obamas-plan-to-kill-armed-pilot-program/