Well I guess we'll know the truth of it soon. The HH series of novels are rapidly approaching the Battle for Terra. Assuming they don't stuff another couple years worth of short stories in there. (The most recent entry is made up of short stories ranging from 2 to 10 pages. Seems like every couple of books they release that actual deal with history, they insert a filler novel in there.)
Yeah, Legacies of Betrayal was a really weird book. It had one (or two?) longer novellas, then a few normal-length short stories - and a lot of bizarre, super-short stories that were more like single scenes that really didn't show much anything.
@Xant:
I haven't read each and every book, but I can recommend the first five or so - not because they're necessarily super-good, but because they're kinda essential to understanding the whole thing - then Legion, Mechanicum, Tales of Heresy (this is the best of the collections by far), A Thousand Sons, Prospero Burns, Know No Fear (I used to think McNeill was the best when it came to writing scenes of combat and destruction, but hooooly shiiit Abnett), Unremembered Empire and Scars.
I'm sure you'll choose which ones interest you most, and people might disagree with me here, but these are my favorites. I wanted to like Fear to Tread (I want to see Sanguinius in all his glory, damnit), but it was kinda dull, bah. The Outcast Dead and Nemesis also focus on something else than Marines, so that already makes them stand out - they have some cool bits, so go fer 'em too.
I haven't read Battle for the Abyss (I think), Fallen Angels, The Primarchs, Shadows of Treachery, Angel Exterminatus (though I might get it next), Mark of Calth, Damnation of Pythos or Vengeful Spirit, or any of the audiobooks and whatnot. Are these any good, anyone?