My problem with Legacy is that it's not really a cohesive story. It's just an advertisement for the upcoming arcs of the books under this "Legacy" banner.
Wolverine is back, so what? The Frank and Val reveal is cool, but has shown us nothing new. We already knew what they were doing and this doesn't promise us that they are coming back soon, they could still be gone for 3 more years for all we know.
The most interesting aspect was the Celestial story, all the other plots should have been tied to that. It would have been much cooler for me if the FF reveal was tied to whatever that Celestial mystery, like if they haven't returned yet because of it. It would have also built up hype for Two-in-One as there would be a mystery to how missing FF are doing.