On the Unlanded Nobleman

Unlanded noblemen make lots of sense as PCs, and here are some reasons why:

• Provides an end goal more tied into the world than "amass wealth, follow DM's railroaded plot", while also granting more focus than a completely aimless sandbox game and maintaining some degree of autonomy.
• Combines well with themes of good vs evil if the PC's title was usurped by a tyrant.
• Rather than meeting in a tavern, you meet in the court of a lord sympathetic to your plight (or who just wants to press your claims, revoke your title for treason, and then claim your land for himself...  This post brought to you by Crusader Kings, where I am occasionally That Guy)
• Nobility makes sense for the adventuring professions - traditionally the clergy and knightly classes were common places for noble scions.  Rebranding thief / bard as courtier could work in a late Medieval setting, or they could just be minions, while I expect wizards might work much like knights, in that it's expensive and childhood-consuming to be trained as one, and so the vast majority of wizards are from noble backgrounds.
• Supports play as the "Band of Misfits".  I've never met a group where everyone could get on board with a theme, like "we're all dwarves", or "everyone's a linguist".  If you're all foreign nobles and exiles in someone's court, it's less straining of credulity to have a Scot, a Russian, an Arab, and a Norseman all operating together (particularly if they're the only foreign nobles in the court; outsider flocking and accompanying party cohesion ensues).
• Noble status provides some degree of protection from the consequences of the usual abuses of commoners, henchmen, and hirelings by PCs.  Eccentricity may still result in ostracism among the nobility, but noble status provides some measure of protection from being stoned or burned for heresy and public indecency.
• Abundant reasons for travel,including:
•  "You are beginning to strain this lord's hospitality; perhaps it's time to hit the road again"
• "The lord three counties over had gone to war against [orcs | rebels | heathens | infidels]!  Perhaps if you can be of service in this, he will support your claim to the throne."
• "Your spies tell you that a powerful vassal of the unrightful lord of your land has fallen out of favor and is on the run.  He might be induced to join your cause if you can keep him from being captured."
• "A distant lord is holding a tournament, and to the victor goes a boon and the glory of minstrel's songs."
• Similarly, "The Grand Moot of the Northmen is in a few months.  Their warriors will gladly follow any leader they think will lead them to conquest and glory, but any sign of weakness could see you dead or enslaved instead of fêted.  Also beware of polar bears and frostbite."
• The essential theme here is that instead of adventuring solely for the acquisition of personal power, one adventures in order to gather allies to support their claim.  Public support becomes as precious a resource as gold, and good works can be undertaken for the sake of the allies they might bring (rather than confining one's activities to amoral money-motivated dungeon-raiding).
• Whenever things get boring, you can send assassins without breaking verisimilitude at all.  Maybe they're working for the Usurper, maybe for a cousin who also has ambitions on your throne, and maybe for someone you've irritated during the course of the campaign, but assassins should never be in short supply in a courtly setting.
• Precedent in fiction: Thorin and the dwarves in the Hobbit are out to reclaim their inheritance of land and treasure.
• Precedent in history: Many of the Spanish Conquistadors were unlanded (hence expendable) sons of minor nobility

 In sum - unlanded noble PCs (either due to being 2nd or 3rd in line, or because their rightful titles have been usurped) provide a very good combination of resources, training, and liberty.  So why don't we see them more?  In all the time I have gamed, I think I've only seen one case where PCs were from minor noble families (there was another where a PC was revealed by the DM to be from a ruling house late in the campaign, but that's a different matter).  I think that lack of system support contributes significantly.  If a DM has no guidelines for what to do with realm-holding characters, it becomes likely that characters will only receive kingdoms in the very endgame, as credits roll, Aragorn-style.  Players know this (particularly as a result of the implicit social contract that if you're no longer adventuring, you're no longer a PC), and so avoid creating characters who have realm acquisition as a goal.  I have also seen DMs push players away from rolling noble characters, possibly due to perceived gaining of advantage at no cost, and possibly due to a pessimistic expectation that such PCs are unlikely to fit into the world.  I know I have done so for both of those reasons, and in retrospect this was a poor stance to take.

So: next time I decide to run ACKS at 5th level, unlanded nobility will be on the menu (doing so at lower levels seems liable to completely depopulate some of the smaller noble houses before anyone gets anywhere).