My overall impression is that the worse the growing environment, the more likely pruning is to help rather than hurt.
Pruning diverts energy from longer stem growth into short stem plus pod. That can help you bring to term the first wave or two of pods in a short growing season or with suboptimal conditions but when you end up with a short bushy plant from pruning, at some point it's shading itself more and runs out of sites for new nodes without again trying to grow more stem (higher ratio than it previously had). Plus, past a certain point the plant is more likely to have limbs dragging the ground while loaded with pods, if they don't break off first.
IMO the most important factor is a lot of sun and warmish-hot temps but not too hot, of course allowing for enough water, soil. I think we need a test where the plants achieve a lot more growth per season as well as a far larger sample size to draw a final conclusion, and that for Stefan in Canada, pruning might be the right choice to get a wave of pods in before it gets too cold, but it may be far more limiting to larger plants in better climates or with longer growing seasons.
None of my first-year chinense plants were that small nor produced less than hundreds of pods and I don't have a particularly long growing season, just a nice temperature zone for limiting summer highs, and longer than in Canada. Each successive wave of node splits almost doubled the seasonal yield up to the point where pods didn't have enough time left to ripen before the cold weather set in. I am not against pruning per se, but in my climate it doesn't seem useful. A secondary concern would be if you're overwintering the plants, a small bushy shape can only do so much the next growing season before it's again shading itself a lot and dragging its limbs on the ground.
On the other hand, if you don't at least trim back a plant "some" before overwintering, it takes up a lot of space.
