She has every right to be, she's easily the most powerful of the Scions, and she's worked for it, taken risks and beat the odds, twice. I've found her to be the most blunt of the group, the rest (aside from the twins I guess) are all shady as heck and never seem to give a damn about the WoL's actual wellbeing. Thancred hasn't been likable at all since Heavensward, and Urianger needs a smack across the mouth for previously stated reasons.
Also, she's the face of the game, and generally the first representative to show up in any collaboration because she is instantly recognisable.