If there's a decisive turning point for the rest of characters' (those out of Roy's closest circle) and for the readers' perception of Roy, it must be the Maria Ross cover-up. A much more clear-cut view on Roy is offered during the Ishval flashbacks, but I see it as a continuation of what the Ross incident made obvious, and of something the storyline were always pointing to, regarding Roy's true character.

It all started as a chance meeting between Hawkeye and Barry the Chopper, but it ended up being a mission to save an innocent life and eventually, a huge progress in exposing the homunculi's plans. Roy proved he had quite an open mind when he agreed in making a deal with Barry -- that is, after he made sure he wasn't Hughes' assassin. Roy knew it was a risky move, and even offered Falman a way out, which the man turned down immediately, of course.

     

And thus Falman was assigned to work undercover and look after Barry, while the rest carried on with their activities. It was then, that Maria Ross was arrested for the murder of Maes Hughes. And however little was Roy's knowledge about the woman (he could only have heard of her through Armstrong, but that's unknown to us still), he decided to believe in her innocence, with only suspicions and his gut feeling as a back up.

He developed a plan to let her escape, unknown to everyone except to the people closest to him (that is, Hawkeye, Havoc, Breda, Fuery and Falman) and Barry, who in fact helped with the rescue. Unknown to us, readers. What was shown to the outside was Roy killing off Ross, without any contemplation or remorse, and under the excuse that he was allowed to stop her from fleeing at any cost. And that's what Edward saw. It's true that these two have a somewhat difficult relationship (see Edward's relationship section), but the fact that Ed was completely baffled about what he thought Roy had done, shows that no matter what it looks like, the boy considered Roy to be a decent man.

At that moment, Roy apologized to the brothers for hiding Hughes' death from them, but kept under his cool façade everything concerning Maria Ross. Still, the one more hurt by Roy's deception was Armstrong. Up to that point, the man had given Roy so much support and had such an unwavering faith in him, that this revelation (Roy killing his subordinate in cold blood) left him crushed.

And despite the need to keep everything completely under wraps, Roy couldn't help but reveal to Armstrong his true intentions, in a way only Armstrong would find out. It says a lot about Roy that he can't stand seeing the man lose faith in him, for Roy is probably the only one Armstrong can really trust. It also says a lot about Edward that he ended up being doubtful of Ross' innocence, instead of doubting Roy's judgement. Although being totally fooled by Roy's tricks pissed him off quite a bit too.

All in all, this incident caused a crisis of faith for some people, but the true meaning behind this charade only helped to strengthen the trust in Roy and have a new understanding of him. It also made Ross gain endless admiration and gratitude towards the man, up to the point of relying her own life on Roy, in case he someday needed to make use of it.