Interesting teaser. They clearly want to distance themselves from the previous mess they made, obvious Nolan tone, whether that turns out to be good or bad, we shall see.
From comments I've read its clearly not something actual F4 fans were hoping/expecting though so maybe knowing little of the source material in this case helps me, but it at least made me interested in the F4 for once.
I'd say its better than the Ant-man teaser but below Avengers and Star Wars.
I'll give it a 7 for now but could go either way still.