Because I'm now 41, my memory is probably hazy, but I don't seem to recall such a long time between official announcement and release of 4e. Did we wait this long last time?
The smart money (i.e. mine) says 5e will launch at GenCon 2013, which is about 18 months from now. In the meantime, there'll be the playtest, although I don't think that even WotC really understand how that'll be implemented.
My guess is that we WON'T see the kind of open playtest with free downloads that Pathfinder had. My instinct is that to participate in the 5e playtest, you'll need a DDI subscription and you'll need to sign an NDA. But we'll see!
Put me down for this prediction right now: There will be at least a handful of people, at launch, announcing that they intend to keep using play test version N for their own campaign, because, "after that point, WotC really took it in a direction we didn't want to." In return for not being entirely in sync with the new shiny launch version, these people get to start early.![]()
You know what? I'm frustrated at how long 5e is gonna take. Reply to Thread
My guess is that we WON'T see the kind of open playtest with free downloads that Pathfinder had. My instinct is that to participate in the 5e playtest, you'll need a DDI subscription and you'll need to sign an NDA. But we'll see!

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.