Steve Danuser is the ex-Creative Director at the shuttered 38 Studios, and in light of that leaked trailer
seen earlier today he's posted a few bits of context
for the video. As you might have guessed, the posted trailer was entirely a work in progress, with most assets and even the script likely set to be replaced before it appeared before the public.
The trailer itself would have been a launch trailer, likely also released with some in-game or hands-on footage, and the illustrated look seen in the trailer was planned to be a characteristic of the game itself, used to introduce the game's various races and factions.
As for the tri-circle logo, which seems very similar to the recently revealed Elder Scrolls Online logo
: Danuser says the design is coincidental, and that the two MMOs were using the same themes. 38 Studios' logo was put together before anyone from the team saw what Zenimax Online was working on. "That's what you get," says Danuser, who fondly remembers working on putting the trailer together, "for basing your IP on classic themes."