Regula van Hydrus sacrifices himself to save a child towards the end of The Warring Triad quest chain. This happens after he temporarily aligns himself with the Warrior of Light and Scions in an effort to help take down Zurvan.

Gaius van Baelsar is revealed in a side quest in The Fringes to have put an end to chemical warfare, seeing it as distasteful.

A Garlean Centurion named Baut is involved in a quest chain in The Peaks. It is revealed that he was revered by the people living in the settlement he had control over as he was an honourable man who put a stop to the abuse of his predecessor. Rather than fight, he surrenders the settlement to the Eorzean Alliance upon their attempt to liberate it, yet the people threaten to kick The Resistance for fear of them taking Baut away from them. The quest chain ends with Baut being pardoned and settling down with an admirer of his.

Following on from Baut, he outright states that although the likes of Gyr Abania and Yanxia suffer under Garlean rule there are other, prosperous provinces elsewhere who are doing very well for themselves.

The Prima Vista situation is as Dualblade stated.

The lore book has some interesting nuggets, too. It reveals that the Garlean flag is meant to represent and honour all those who perished in Garlemald's name.

It also reveals the history of Garlemald, touching on the horrific abuse Pureblood Garleans suffered in the past. Their inability to manipulate aether led them to be driven out of fertile lands, forced to carve out a living for themselves in a frigid wasteland. This hardened them, causing them to live in small numbers and with no luxuries until their fortunes shifted upon the discovery of how to turn ceruleum into a power source for Magitek.

Moving forward, we will no doubt see more of the above. The developers have been very careful to keep each Legion as its own separate thing, yet so far we have mostly only seen Garlemald through the eyes of the Eorzeans. We will inevitably see even more positive things associated with Garlemald as the story takes us closer to it.