MMO stories tend to be weaker than single player stories simply because they have to account for the player.

Anyway the characters on both sides are not meant to be black & white. They are in all shades of gray.
This makes them believable and more realistic and meant to keep the question of "should I be working for them" valid at all times.

How am I suppose to hate that guy!
Because you are not supposed to. Gaius view is skewed from an Eorzean perspective but entirely valid from Garlemald's.

From a military standpoint, the greatest victories are won without shedding a drop of blood. Gaius wins by intimidation (threats, ultimatum), subterfuge (fanning Ala Mihgo unrest) and resorts to brute force only when necessary.

Nero on the other hand will probably end up as the psychopath taking over the White Raven's role.