My point about education is that at present most commoners have to take what is fed them. They accept the inequality under the law because the nobles and Chevaliers claim Divine Right not just to explain the inequality in their position in life but also their treatment of those less fortunate than themselves. Trying to get them to change their secular laws would be a uphill struggle as Celene herself admitted. However, you don't have to, you just point to a law that is already part of the culture and that they use to maintain their lofty position. You appeal to faith in the Maker, belief in which is probably much stronger among the commoners than it appears to be among the nobles, considering how fast and loose they play with the tenants of the Chant of Light and their wiliness to use a shameful parody of Andraste to make a political point. The Chant of Light is a splendid indictment of the abuse of power, magical or otherwise. It does not insist on absolute equality of position in society, it does insist on equality in the way people are treated. So to murder a noble without cause would be just as bad as murder of a peasant without cause. Hopefully that would avoid the problems of revolution since all you are asking is for the law of the Maker to be applied across the board without distinction.
The reason the Qun appeals to so many elves is that it would appear they would have fairer treatment under its system. Now may be the Qun are a bit crafty and haven't told them the full implications, because social mobility is just as impossible in the Qun. You may not have nobles and commoners but you do have the "role" you are assigned to, from which you are not meant to aspire to anything else. Everything in your life is directed by the triumvirate. In view of the threat posed by the Qun of infiltrating the ranks of commoners, in particular the elves, this is why in a way it is in the self interest of nobles to improve conditions and education, so they realise that living under the Qun would not necessarily be any better.
Actually of the countries we have seen the inner working of, Divine Right doesn't exist in either Orlais or Ferelden. In Ferelden the aristocracy so to speak is tied in large part to land ownership. You are a Bann or such because your family has historically owned the largest portion of land in that area. The royal family of Ferelden is all tied to the first family to unify the lands of Ferelden by war, divine right doesn't exist.
In Orlais, it is all built on power and the game. Celene wasn't even thought to be a candidate to be Empress until she outmanouvered Gaspard(the odds on favorite at the time) and the others who were in line to claim the throne.
Never once is it mentioned in either of those countries that they rule or are nobility because the Maker said they were. Especially not in Orlais. If Divine Right existed in Orlais, the Great Game couldn't function as it does.
As for social mobility, not certain about Ferelden, but there are references in Orlais to elvish merchants, elves owning warehouses and property, and even elves having their own servants.
Now, I will also point out what I find interesting about the perception most have of Orlais is based off of Ferelden based perspectives from DAO. I am certain some of those pro ferelden/anti Orlais viewpoints will be accurate, but knowing Bioware and their penchant in DA for having in game character perspectives not always be accurate, I can see there being quite a bit about Orlais that isn't as it was presented in DAO.