What are some of the games you've played that you thought had the potential to be really great or epic, but fell short because of one or two flaws?
The best example of this for me is Grandia III. The graphics in the game look stunning - some of the best I've ever seen. The characters, especially the early ones, are well developed and have good backstories. But then at one point, two of the best characters leave and never return, leaving their subplots and storylines completely unresolved. From there, things start to go downhill a bit on the story.