They've revealed little things at the Convention, but I think it's not much (like the names of the X-wing model and that sort of things. Biggest thing I've heard of were the new names of the former Empire and former Rebellion 30 years later. They're intriguing, but not very revealing.).
Otherwise, the trailer merely built on elements from the teaser. We've barely heard a word from the main cast (I can't recall a line in fact...) , they've not even shown Leia or Luke, I don't really see them going nuts in September with a very revealing trailer 2. I think that as usual with SW the thing to worry about for the general public will be the TV ads. Those they make in a load of versions, and together they end up showing way more than the trailers. For the rest no doubt SW.com will go nuts teasing the fans in the last months, as they always did... the crawl, character bios, planets .. and revealing behind the scenes stuff, etc. Nothing very hard to avoid. For TPM I didn't follow development much at all - just saw one trailer - and despite being on the net every day I barely knew anything of what to expect.
While not showing faces, would you not agree the mechanical arm with R2 indicates that the hooded figure is Luke, and that when he's speaking of Leia and the next hooded figures receives a lightsaber, that that is clearly Leia?
