He isn't a no brainer for the simple reason he was a personnel man only and not a field general or owner. Kind of like being a punter or kicker or safety...positions that simply have not merited the respect/consideration they perhaps deserve. In order to just be considered Polian has to be exceptionally special. HC's and GM's have spent decades pointing impact fingers at each other, and at the end of the day the nod has always gone to the HC's (credited if you win, blamed if you don't) and above all others the HC's who are also GM's and franchise architects - which would be Belichick. Which is also why Pioli will never merit serious consideration UNLESS he makes a ring winner AGAIN out of some team where he actually had total control.
And again, what he did in Carolina had less to do with Bill Polian's genius than the league's determination to set expansion teams up to be worth the price of admission. As another poster pointed out, both Carolina and Jacksonville's success that season led to the league changing the formula making it harder for future expansion teams to get a leg up on the competition out of the gate. And Carolina went into the crapper the following season...after which Polian moved on to Indy...and remained there as the team and the organization Bill built there just unraveled and fell apart.