When someone wants his advice to be heard and followed, he usually keeps the changes small, like if you want to advise your friend to change his $5000 car, you'd probably offer to buy a $10K or $20K but surely not $500K. Instead of offering to involve Aharon and his sons (5 men), or the Heads of the tribes (12 men) or the Elders (70 men), he offers to jump straight to a total of 78,000 judges.
Is this way of thinking reasonable?