I think that your analysis is very much in line with Martin’s intent. You might as well mention that Martin applied for, and received, conscientious objector status during the Vietnam War.
I think, though, that you give away a little more than you need to in the end. The world of GoT consists only of the main books and the "Dunk and Egg" stories taking place in the near-past, so there’s not a lot of source material that "true fans" would know about. The wars we know about are:
1. The Andal invastion, occurring ~5000 years before Aegon’s invasion. This war lasted hundreds of years and eventually displaced most of the First Men to the North and the Children of the Forest to Beyond the Wall. The North put up the most resistance to maintain autonomy from the Andals, and eventually the Andals relented (which is why the Northmen revere the Old Gods, etc). However, in the coming centuries dynastic marriages have removed most of the Northmen’s distinction. The Rhoynar — Essosi invaders of Dorne — met with a similar result.
2. Aegon’s War of Conquest. This works out pretty well for Aegon, but because of his immensely superior firepower, he was uniquely situated to make some long-run forecasts about his chances for success. For the smallfolk, there was virtually no long run change, but they were devastated by the war. The Kings of Westeros would have done well to simply lay down arms from the beginning. Dorne maintained their autonomy for some time, but some 150 years after the conquest they were forced to bend the knee as well.
3. Various civil wars during the 300 year Targaryen dynasty: the first and second Blackfyre rebellions, the Dance of the Dragons. The smallfolk certainly suffered, and usually the only thing at stake was who would sit the Iron Throne, Eventually these wars led to the extinction of the Targaryen dragons. The Reyne Rebellion against the Lannisters didn’t end well for the rebels, as we know from the song. You can count the Faith Militant uprising among these conflicts.
4. Various wars against various "Kings in the North," invading barbarians from Beyond the Wall. Its unclear what the real purpose of any of these wars was – ostensibly, to prevent the wildlings from raping and pillaging the North – but much of Jon’s POV functions to show that there is a better way.
5. The War of Ninepenny Kings is a possible candidate for a war that ended well. Kings from Essos gathered under the banner of the last of the Blackfyre pretenders and were plotting an invasion of Westeros and won some early key victories. They were put down by Aegon V’s forces.
6. Robert’s Rebelllion. A good candidate on the surface, but doesn’t hold up. As you’ve said, the reign of the Mad King probably wasn’t so bad for the smallfolk, only a small group of elites. The catalyst for the actual rebellion was the "kidnapping" of Lyanna Stark, strongly indicated to not be a real kidnapping. Brandon Stark rode to King’s Landing and demanded Rhaegar’s head, and Aerys responded very harshly. Arryn started the war rather than hand over the heads of Eddard and Robert. That would have been unjust to be sure, but thousands upon thousands of people died during the course of the war. Eventually Robert, a poor ruler, is put on the throne. The power vacuum following his death is a major catalyst of the War of the Five Kings.
I think GoT is very much an anti-war story which plays on fantasy tropes about heroic, chivalric wars.