I think "when it's ready" has kind of been a term used during early development stages, and has probably resulted from the lashings that occur when a rough release date is set and the devs aren't able to hit it (this is especially true in modding circles, though I don't understand the spew of venom on folks that are doing stuff for free out of their own generosity).
I think this is a better approach than other methods of marketing, such as complete silence (I think we know who) without any sort of response to loyal fans.
I'm also glad to see that about half this teaser was actual gameplay, as opposed to a lot of new game teasers which are nothing more than rendered animation, or even worse, the "live-action trailer" (good lord.....who thought that was a good idea?)
Even though its pretty short, we can see a bit of where they're going with it, so I'm pretty happy with what information we were given.
And Frostbite 3? Yes. I'm happy about that.