Yes, though I should first say that 'adventurer' is not a recognized profession in my world. The closest equivalent to adventurer as you use the word is 'mercenary' or 'sellsword'. Adventurer as D&D players use the word carries the connotation of hero or problem solver, and is positive in the way that the English word 'Knight' is (and not in the negative way that Ritter is in German). The word adventurer isn't in common parlance in my world. You'd never say, "We should hire adventurers."
For what it's worth the modern connotation of adventurer as a positive thing is recent. Go back 120 years and the word meant something closer to bandit or maybe highwayman.
*snippy snip*
And if they were to leave and come back with about twice as many levels, it wouldn't be long before everybody was deferring to them out or respect or fear or both.
I want to play in your game.
Your world is better thought out and shows more historical nuance than most.
Historically, most noble houses got their start as basically bandits (or adventurers) that settled down and gave themselves airs. When it was less trouble for their neighbors to play along than to kick them out they succeeded and a noble house was born.
And attitudes and laws vary by place. In europe you has an unarmed (mostly, there's always flails and pitchforks) peasantry that was down trodden and a fairly brutal aristocracy. In the UK you had an armed yeomanry and the nobles either used a lighter hand or discovered that formenting a rebellion amoungst people who are required by law to practice the longbow is a bad plan.
Now where D&D departs from history is in the personal power of high level characters. In the modern era it's pretty easy to aquire weaponry equivilent to mid-level D&D magic, as a society we're still trying to work out exactly how to deal with that. A lot of places in the world have rather spectacularly failed to deal with the fact that with commonplace weaponry you can't crush your populace for very long. There are some exceptions, which mostly run as brutal police states which put most of their energy into crushing the populace while simultaneously telling them how good they have it. It's worth noting that if a band of 'adventurers' showed up in a police state they would very, very rapidly have to make a choice between working for the state, or trying to bring it down. Either way they'll probably be killed.
The point is, that you need to, as Celebrim has, think about your world and the people in it. How have they been shaped by their geopraphy, history and culture? What is the basis of the laws? (There are two basic systems: What is not permitted is forbidden, or What is not forbidden is permitted.) Are you using the medieval model where you sort of have a net of different power structures which police their own and get prickly about jurisdiction? (The craftsman was making a statue for the Bishop. Is his murder a guild matter, a church matter or a city matter?) What are the local monsters and how has their presence impacted society?
Suggested reading:
Guns Germs and Steel by Jared Diamond
The Night of Madness by Lawrence Watts-Evans
A medieval reader
The Judge Dee novels translated by Van Gulik