Things R better in 4's

Our state of the art computational fluid dynamics system showed the penta rotor would suffer from extreme weather vaning of the tail rotor. Yaw provided by the 2 front propeller torques would not be enough to overcome weather vaning. In the worst case, U would have 2 front rotors stopped & be completely unbalanced again.

Moving the tail rotor closer would make no difference. You'd watch a line of 3 propellers mysteriously turn perpendicular to the wind.

U can pile on a servo to control yaw by deflecting tail rotor thrust & add more weight.

The main problem is preventing rollover on the ground. U definitely need heavy rotor shrouds. Just because Draganfly sells underslung propeller craft for $17,000 doesn't mean you're not going to break tons of propellers. Notice how draganfly.com shows plenty of hand launches but never the landings?

Finally, we have shortened flight time from lifting a 5th motor.

There's not much U can do to increase quad rotor performance. U can reduce flight time. U can increase weight. U can reduce payload. Everything you can do to the basic 4 rotor design is just moving performance from 1 area to another.

Your best option is more software to handle unbalanced payloads gracefully. Others don't clamp PWM values. They reduce collective when a PWM is saturated. Thought that was stupid so we didn't implement it, but clearly a powered attitude controller is different than a swashplate.