I swear Boromir had more character development in Fellowship Of The Ring (and that 5 minute part from the extended Two Towers) than any of the other characters did in three films
I'd agree, but that's because all the others started out as paragons of virtue and finished up as paragons of virtue. It's why I'll always like the Fellowship more, despite the more heavy action in the later two, I couldn't have cared less whether they succeeded or failed, or lived and died.