Here is my .2 cents on defoliation. To preface there are many growers and styles and each farmer has to find what worx for them and the strains they are working with. But a lot of growers don't run a strain enough times to really get to know it. Mostly due to chasing the new strain/flavor of the month madness. With that said,
Each seed has a pre-programmed genetic code. This code covers everything the plant needs to be the individual it will be. You all know genetics right? it sets up everything to plant height, color, stature, color of flowers. Internode location, bud sites, eye color lol etc.
If given all the required elements, water, light, air and nutrients, the plant if not stressed or left to grow outside of perfect parameters with enviro's will grow to it's pre-determined genetic potential, typically. The number of leaves is also coded and in an effort to get to the plants natural potential it grows what it needs to fuel the plant to that end.
I have always been baffled why in knowing this, that we would want to strip the plants main source of energy away from the plant. Leaves drive photosynthesis, so in theory when we defoliate aren't we taking away from the predetermined amount of solar panels the plant needs to get to it's final place. I am not to the place yet where I think I know better than Mother Nature and the code is set up this way for a reason. Same reason I also frown on flushing when growing in organic living soil. A lot of strains pack on the final weights in the last few weeks of flower, so why then at this stage do we want to starve the plant when it is at its peak of flower production. But that topic is another can of worms best left to another thread.