I think if you have immersed yourself in all the rumors and spoilers, you do get a pretty decent idea of how this film s going to present. There are many elements that are still not known and are pure speculation. Having said that, the story that I have developed in my head is very tight and exciting and makes in universe sense. For what it's worth, it seems to me, as someone as spoiled as i can be at this point, that it's a terrific story and all that remains is how it's executed and acted. Based on the trailer and teasers, we get a glimpse of that and to me it looks like they nailed it.
John Viggnochi of Disney Interactive Studios was interviewed the other day and he has read the entire TFA script and was extremely excited by it. Now, he does work for the company, but almost universally people in the industry who have read the story have been full of praise. So that's a bit more tangible evidence they have a great product. At this point if there were real problems with the film, we likely would have heard rumblings to that effect.
I think there are far more reasonable reason to be very positive about the film then pessimistic at this point.