The problem I ran into with Inward Perfection is that you're supposed to be peace-loving xenophobes who just want to be left alone. You are not only prone to getting into fights with neighbors because of the border friction, but you have to spend influence to keep the peace, AND you have one fewer envoy to the job with. It ends up with a very counter-intuitive result to the build. I'd make the following changes to Isolationist Diplomatic policy with Inward Perfection:
- -50% border friction, instead of +200% border friction.
- +100% Diplomatic Influence cost, except for Non-Aggression Pacts. Neither you nor the signing empire pay influence for Non-Aggression pacts.
- 0.50 cost to send an envoy to harm relations. Sending an envoy to improve relations with direct neighbors is reduced to 0.0. Good neighbors, good fences, everyone is happy.