Wing area distribution (shape) and dihedral on rudder/elevator sailplanes does have various effects on maneuverability. Too much polyhedral can make the sailplane too stable. Not enough and you can't turn it with the rudder.

Weight and airfoil will affect performance. A thick airfoil on a light plane will make it slow. A thin airfoil on a heavy sailplane will hurt the distance to altitude ratio. All factors need to be considered when designing a polyhedral rudder and elevator RC sailplane.