Once Upon A Time There Was A Revolution wasn't weak at all. And the casting was great.
The enigmatic touch of the names; 'Juan' and 'Sean'... represent the average 'John's': the nameless men who are swept-up in revolutions they have no control over.
Looking back, 'Sucker' worked in the script. It elevated the 'peasant' or 'peon' connotations that Juan was used to... Being called a 'sucker' in the moment before the explosion made him an equal with the men and forces around him.