Depends on the story. Some stories require kings and queens, some require peasants. My stories -- at least in high fantasy -- tend to be about the younger children of nobles, or their children, or something like that. High enough status for some mobility and clout, a far amount of freedom stemming from a lack of duties, but not enough to let them easily overcome some obstacles. Steampunk, of course, has more flexibility. A lower-middle class hero, or even a working class one, or a peasant, could move around in a steampunk world the way no one could in a high fantasy one barring very rare magics. (Otherwise you would start to get into magitech.)
But when they interact with others the social positioning can be crucial. And it does raise questions about how quickly you can convey to readers what the social structure is, and what the complications are. Merchants, for instance, are often categorized as the lowest of the low -- less than peasant farmers. They do tend to be possessed of that great solvent, money. That's one reason why miles came to mean "knight." If you thought it meant "soldier" you were right -- in classical Latin, and even during much of the Dark Ages. By the time of the High Middle Ages, merchants were started to get rich enough to have clout, and the warrior class looked for a ceremony to mark them out and make it clear the difference. It kinda backfired. A knight does not have to fight or even be capable of fighting; he only needs to have been knighted. The most unfit merchant can manage to surviving a knighting ceremony. And there can be other conflicting things, too, like education.
One novel I remember well is one that wizards as skilled craftsmen, the level of guildsmen -- a fact for which noble knights have great contempt. Many high fantasies treat wizardry as social status. Though they do tend to have lower levels, down to the herb witches and hedge wizards, you can't count on it. To be sure, many a king had an alchemist or astrologer hanging on his court so that has some verisimilitude.
And then there are the shaky standings of unusual births. The children of concubines may have some legal standing, but usually inferior to that of a wife's child, if indeed they are not simply bastards, and the children of mistresses have no legal standing. Many a father, especially one of high birth, has been unwilling to accept that. Wills, patents of legitimacy -- when John of Gaunt married Katherine de Roet and legitimized his children, he made the daughter of a herald who had been knighted the highest ranking woman in England (since the king his nephew was unmarried). Even without such legalities, it can be very foolish to throw about a technical legal superiority.
Which will affect any character's freedom and powers, which are the wellsprings of conflict in a story.
Of course, then there are the readers. Some of whom find it very hard to get into the notion that other people really did live in other social structures, and wonder why a character doesn't just ignore the strictures of his birth. More of whom find it hard to believe that other people really thought their social structures were right and just and the universal natural order, even though that's the natural human reaction. I have read querulous questions about why the characters don't immediately regard slavery as an abomination, or don't try to install democracy.