Switching to a F2P model has saved floundering MMOs before. If anything, it can mean an influx of players and cash. The trick would be making the transition gracefully, setting up an alternate revenue stream that doesn't consist of pay-to-win or obvious nickel-and-dimeing headaches.
Wait, they pulled that off in 12 hours? Holy crap.
But yeah, I remember reading that they didn't say they wouldn't make major expansions but rather that they wouldn't have stand-alone expansions like with GW1. This is in addition to regular, free content updates.