You are mistaken.
A battle cast circle lasts 1 hour.
A spell-crafted circle lasts 5 days
A ritually cast Limited circle last 5 years
Would you care to be more specific about what you don't like?
At it core level, I do not think adventurers should hold legal sway over other adventurers. Nobles do paperwork, adventurers do work.
The overall population of the town was about 18 people last market day. You've listed 7 roles. One of which needs to serve as a consul having multiple members.
I do not like the concept of citizens and non-citizens. If an adventurer comes to town to help, they should not charged for magic item identification because they haven't been here before.
You're paying 'administrative pay' to a bunch of people who aren't doing anything but restricting people. If you can give me some examples of how any of these noble roles help grow the town, I might be more agreeable.
I'm not sure what the tax money will be used for, you say 'buying planar asylums' but that will be based on some nobles' preference.
What qualifies income? If I get paid 100 gold to fix the planes but I had to buy 95 gold worth of scrolls to do it, am I taxed on 100 or 5?
If we have to satisfy some qualification of the Empire, then we should do the minimum required, or not be a part of them.
Adventurers don't do well with bureaucracy.
-Gideon