º Diablo in Diablo II.
One of my big problems with Diablo II is that Diablo is the only character given even a modicum of development or motivation. He has a prison to escape, a Hell to resume managing, and a world to conquer. The player character is there for ... money? Maybe? Being that each of the player characters can only muster a single line of dialogue between each act and after each boss fight and has absolutely no backstory to speak of, I can't say I was ever too attached to any of them.
A few others, so that I don't write a huge rant about how overrated and awful Diablo II is....
º Doctor Carter in Surrogates and the Cylons in Battlestar Galactica (reimagined)
I hate it when a story arc turns into a "TECHNOLOGY BAD!" rant, so when Surrogates started down that path, the film got frustrating for me. By the end of the movie, I wanted Bruce Willis and his whole "Surrogacy must be stopped!" posse to eat a very large bullet. Likewise with the very last episode of BSG. During that last bit of the final episode, where the writers flipped their lids and suggested that we, the humans of the nonfictional world, should fear all forms of robotics, I found myself retroactively siding with the Cylons (or it would have been retroactive, if not for below).
º The Cylons in Battlestar Galactica (reimagined, again) and the Shivans in FreeSpace 2
Two different series, but much same reason. The humans in BSG and the GTVA in FS2 were both totally out-matched by their opposition. I don't think they should have gone down without a fight in either case, but in both cases, the final outcome felt forced. FS2 did better than BSG in this regard, as the desperate last ploy of the GTVA had some basis in how the FreeSpace universe worked. BSG just kind of threw in a super-centralized Cylon hub that was so super-duper-important to the Cylons that it never got mentioned by any of them even once in the previous four seasons, and the impossible-to-win suicide attack against said hub, by a rickety, frail-as-an-autumn leaf, understaffed Battlestar just happened to work out. That stank of a, "Let's wrap this up quickly--oh, and the humans have to win." Such a black mark on an otherwise excellent series....
º The Tank in Civilization I through IV
There's a running joke about the first four Civ games, regarding the ability of the random number generator to allow a Bronze Age spearman to beat a modern tank. Personally, I root for the tank, even when it's my spearman.