Nope
Not so good to have a single app if you have lots of books. Who's on top? Books or magazines? Or just mix by title? I have lots of books and it seems like a mess to me. Seeing how hard it is to sort through lots of books on the Nook and Kindle apps, I prefer the organization of iBooks and I am happy to see my magazines kept separate. Instead of combining them, I suggest that you combine all of your reader apps into a Books or Reading folder, then they are together in one icon and you can select the app you want to read in. iBooks, Newstand, Nook or Kindle. No more issues.