There is NO change to the system you can make - and still have a functional police force - that PROHIBITS police from returning fire while being fired upon. No police officer worth having would work under those conditions.
It's not difficult, cooperate with police - even if you believe they're wrong - and live. That simple rule WILL work more than 99% of the time. If the police are wrong, fight it out in court. That is what CIVILIZED people do.