I'm a well read grad student who's bluntly honest about all things, although I try to be most honest about myself.
Lucy, Elfman and Mirajane all get more full backgrounds that make me more interested in them. In addition, the Phantom Guild tries to kidnap Lucy to bring her back to their client: her father, which ties into her backstory.
But there's a lot more personal connections made, or emphasized, or clarified. The story and personal interactions all get more complex, but nothing earth shattering in that or storyline - which is getting better, too, as Fairy Tail battles Phantom Lord, the guild that tries to take Lucy.
Going to move onto volume eight now.