There's no love affair of the main character in Fullmetal Alchemist.
I agree about Anna, though. She could have been made much more important, or handled better, but she came off as pretty superfluous from the beginning. If they'd developed her differently, possibly given us reason to care about her in a personal way, shown a better development of her relationship with D'eon, then she wouldn't have felt so pointless. I could tell from the beginning that she was fulfilling the stereotypical Japanese Romantic role of 'Faithful woman waiting for her true love to return.'
Durand's character felt kind of standard as well. I feel like there weren't enough risks taken with the characters, especially considering all the situations they were in that could have been delightfully novel, if they'd dared to push the envelope a little more.
I do heart Robin, though. And Teillagory is one foxy grandpa. >:F
[spoiler]Robin's end was more tragic than if he'd just died straight away. First his entire personality essentially died, killing the potential he'd once had to grow up and put his more gentle idealism to action. And then D'eon even saw him being beheaded. Horrible way to go. But you can't really have a happy ending with the French Revolution, can you? [/spoiler]
Overall, it's really well made, and the fight scenes are pretty wicked. But in spite of how much they try, a lot of it ended up feeling kind of soulless. I'm not quite sure what they could have done to make it better, but there was something missing from the characters and relationships.