The Elder Scrolls series gives players an amazing amount of choice and hundreds of stories to immerse themselves in. Too bad the main plot in each of these games amounts to little more than listening while more important people talk about how they're going to impact the world. Oblivion goes so far as to make you the errand boy of the real protagonist of the story, sapping you of any true feeling of accomplishment. The multitude and variety of the side quests help to diminish your feelings of insignificance, but this is cold comfort.
I'm cheating a bit here by putting two games in the fourth place spot, but I figure I shouldn't have to make a choice if both of these games completely disregard choice to begin with. BioWare prided itself on personal stories and relationships with the birth of these two franchises, and both of the latest titles fell well short of fan expectations. Dragon Age II forces you to pick a side and then tasks you with killing both, while Mass Effect 3 rolls off the deep end into metaphysical nonsense with no basis in the political and racially charged storyline. Hopefully BioWare learns from these stumbles and returns to greatness, though many gamers are probably gun-shy after these two titles.
After the Martin-esque political maneuverings of Final Fantasy Tactics and the intriguing personal tale of Ashley Riot in Vagrant Story, it seemed Yasumi Matsuno could do no wrong. Hearing about his involvement in a mainline Final Fantasy title sent shivers down my spine, only to leave me with one of the most depressing gaming experiences of my life. The battle for Ivalice provided little more than a backdrop for inane questing, and the cast (minus foppish sky pirate Balthier, of course) looked entirely out of place and boring by series comparisons. You know it's a bad sign when the guest characters provide more story and direct relevance to the main plot than you do, and FFXII quickly fell of the rails and never recovered from the tired "Evil Empire out to destroy everyone with magic crystals" shtick that was played out nearly seven Final Fantasies ago.
The Xenosaga series was announced while I was still in middle school. At that point in my life I wanted nothing more than to ride in a giant mechanized robot and punch out God, which is probably the reason why I gravitated towards the original Xenogears and Evangelion anime series. And yet, Xenosaga's release in the US left me feeling empty and hollow, much like the game's environments and characters. We were promised a sprawling six game epic, and the first episode in the series felt like little more than a prolonged prologue. Barely anything about the world and overall narrative was explained, and the game ended at what could have been the halfway point of any other RPG. I know it's hard to create a multipart series, but you have to at least provide a substantial story hook. Episode I felt like the ending of the first disc in Final Fantasy VII, and that left many fans feeling angry and cheated. We're still trying to figure out episodic content today, and Xenosaga did little to help the medium in that regard.
The story of each Diablo game is simple; kill Diablo. While nothing is inherently wrong with a simple setup, the disappointment comes from just how much lore Blizzard created for this franchise but insisted on leaving on the outside of the games. I remember poring over the description of the Sin War in the original game's PC manual, and reading through The Book of Cain compendium before the release of Diablo III left me excited and wondering just how wild the story of the third entry could and would get. The developers could have set Diablo III during these times of strife and conflict to move the series away from the rather boring travels of the youngest son of Hell. But guess what; it all comes down to killing Diablo in the end. Blizzard has also relied on the corrupted hero trope for far too long, and it's high time they found a different way to add a twist to the narrative in their games. Self plagiarism is bad enough, but it's borderline ridiculous to use the same premise again and again to drive a story.