So, I'm going out on a limb and saying that Legacy is a poorly planned idea.
It's really just the exact same Marvel comics as a month ago, only with a new story-arc starting in the book (not always a reader friendly starting point either, simply a new story-arc), plus a new banner at the top of the covers to let you know the comic is part of "Legacy".
All the same creative teams are still in place. Most of the books released don't even have "legacy" numbering. Instead of bringing back the titles of Uncanny X-Men, X-Men, or Inhumans (say) so that they can use "legacy" numbering on those titles, they just continue on with the same numbering as last month.
Yeah, I can't see this being the spark that brings readers back to Marvel.