Avtually, it looks like a collaboration between Klingon and Starfleet engineering. The forward and dorsal section look like a bird of prey, while the aft saction looks similar to a Defiant class engine assembly. At the end of the trailer, before the ship flies by, it decloaks...

The Defiant was never a pretty ship in my opinion. But it was an effective plot device in Deep Space that solve the biggest problem the show had: The crew needed to really be able to go places and do it on a propper ship with a propper bridge, not just a cockpit of a runabout. I think that this ship will serve the same purpose. It's an ugly ship, for an ugly job that needs doing so the folks with pretty ships can keep doing their pretty jobs...