Yes! I love the idea! let us create a Bandit Kingdom and become "opposed" by all the major factions and minor factions. That would make it VERY challenging. We could take a castle/city and if they happen to siege and take over it... we could retreat into the bandit hide outs and use them as a trading post/recruitment area (or choose to attack and take over them for our bandits).
Perhaps we could have an addition to the "Reputation"... currently we can choose to be honourable, courageous, etc... but what if we didn't want to be part of anyone's "kingdom politics" and just wanted to be free bandits, living the good life of plundering villages, sacking towns, raiding caravans, etc.
We could become "neutral" with all of the Bandit Factions, looters, deserters, etc... and use their hideouts and camps to recruit, trade, maybe gather missions and "bandit companions". Take over bandit hideouts and make a huge "underground" empire of bandit hideouts until we're ready to gather and attack an entire city/castle. Of course.. all "Kingdoms" and minor factions would be hostile to us... and would probably smash us if we took over a city
but... the life of a bandit is never easy and sometimes a bandit king must crawl through a sewer, before he gets to his throne (if his companions don't slit his throat).
I would have liked to see the creation of camps, where we can use the nomadic tribes that don't want to be part of any kingdom, but are happy to fight for plunder and slaves too.
I imagine a second reputation like:
Thug - You are the lowest of the low, making your life stealing, robbing and general thuggery in cities with the permission of the local gang leader, who takes a cut of the action.
Gang Leader - You've formed your own crew, taken a piece of territory for your self and your underlings extort local business owners and smuggle in black market goods. You pay the guards to turn a blind eye and have minor influence within the city and the nobles.
Bandit - You've gathered a crew of underlings and have a small network of your loyal gang leaders in a few cities to sell loot stolen from villages and caravans to.
Bandit Leader - Your an infamous village raider and powerful leader of gangs in many cities. Bandits from all over know your name and many of them are willing to fight for you. Nobles take notice of you, but you aren't much of a threat yet.
Bandit King - You've taken a city/castle and have thousands of bandits at your beck and call... city gang leaders make money for you in the city and bandit leaders send you a cut of the loot as tribute. The Kingdoms see you as a threat... good luck fighting that 1-2k army doomstack.