The folks in charge of the series now simply aren't as smart or as well read IMO. The last two games have been aimed at the low-hanging fruit (pirates and the American Revolution), while the earlier games dug into less familiar--though incredibly significant--moments and places in world history. The whole PKD-inspired paranoid sci-fi angle has been ditched entirely in favor of crowd-pleasing, big-exploding, Hollywood-style bombast. AC3 (and now apparently AC4) are all surface and no depth.
The big appeal of the series used to be in telling the "secret history" of modern political, economic, and social life. That's all gone. And so is the series' soul.
100% agree.
Imagine a game where you play out the conquest of Constantinople...I love Ottoman and Middle Eastern history, so I'm disappointed greatly by where they've been taking the franchise.