I'm going to go with "an open 4th edition" and clarify by saying "a year and a half ago".
); Ah, what might have been...
The Warhammer 40K RPG - no not "Dark Heresy for Inquisitors and Rogue Trader for traders", one game for everybody!
Aw heck yeah! If there was an RPG where I could play an Eldar Harlequin PC, I would be a very happy person. All of this Rogue Trader super-limited stuff is lame. That's like "D&D but only with fighters who kill dragons!" Sure, it's fun once or twice, but entire groups for entire campaigns? *yawn*
Other ideas are:
3 more in the Book of line for Lawful, Chaotic, and Neutral. Yeah, I said it, a book on neutrality because it is NOT boring. Something like the Book of Concordant Opposition.
Even if Vile Darkness and Exalted Deeds were iffy at points, having those other 3 would be really fun. Heck, even just
Hive and Gear - the guide to Formians and Modrons would rock for me.
I've been tempted to write
The End: A Guide to Ending Campaigns and Destroying Worlds because every campaign should end with something more flashy than another combat, but with a higher level challenge, but I'm sure others could do it far better.
Heck, any ultra-niche whacked stuff that only me and 2 other people would enjoy like deity-level adventures, or a campaign setting focused around Pact Magic, or an adventure path where everyone is a good (or at least neutral) fiend with political maneuvering & plots as dangerous as any combat.
Lastly, this isn't really "published", but how about a D&D movie that doesn't suck?