BioWare always warned that the next Dragon Age (whether it'll be called Dragon Age 4 is unclear) will be at least a couple of years away so the teaser isn't necessarily being coy, it's just that very little final work would've been completed yet. The tagline "The Dread Wolf Rises" is likely a reference to Fen'Harel the elven god of betrayal in the Dragon Age universe. Using the hashtag #TheDreadWolfRises, the latest trailer is heavy on style but relatively light on substance.
No details were provided in the announcement, besides the fact that a new Dragon Age game is now being actively developed. It's been a bit since Dragon Age: Inquisition came out, but you might recognize the name given to Solas, a major character and companion from that game.
Hudson also hinted that Dragon Age was not the only other game BioWare are working on at the moment, saying that the studio has a "few projects" underway and a "few surprises left". It would have been nice to find out more beyond that, but until BioWare shows more, this is your lot for now.
While we won't be sharing any details for now, I can tell you we have been building a new team around a core of Dragon Age veterans, people I've worked with on Dragon Age, Jade Empire™, and some of whom I've worked with since the Baldur's Gate days.
But anyway, I believe what most Dragon Age fans wanted to know was that a new Dragon Age is indeed under development.
We've gathered our strongest team yet and are venturing forth on the most epic quest ever!