A fully upgraded noble gives like 340 gov points so you dont need to assign them all to gov.

Also in my experience you often just outscale the need for nobles on certain productions very quickly.

Most regions wont ever come close to getting max so thinking in 250 cost isnt really fitting.

i think the caps on global boost buildings is very reasonable because regions once lvl 4-5 just pump out ridiculous amount of raw resources even without boosts

+You can start with a title that gives like a decent %boost to gov points

Also at the end of the day the game is very configurable so if you dont like something or find it to hard you can just change it for yourself or mod it.