I'm convinced that there is a part of ripening that the plant goes through which involves the leaves. I don't have the scientific studies to back me up, but there must be a functional design to the question of why a plant exhausts the chlorophyll in the leaves before it drops them. I don't believe that nature designs its systems to work the way they do, without a good reason. Why don't the plants naturally drop their leaves when they are still green and full of chlorophyll if it would benefit the flowers? There must be value in that chlorophyll, right? It must be doing something for the plants to use it up.
What if there was some kind of flavonoid/terpene development that was related to the leaves? Again..."What if?" Would an increase in yield be preferable to a loss in flavor? I would guess that if you were a large, commercial grow op, then yield would be more important. But a small batch, personal-use grower doesn't necessarily have that same goal. All anyone needs to do is to start scoping the buds on the commercial market. The trichomes are clear and the flavor is lacking. Coincidence? I don't think so. The buds look good from a distance. They are big and dense for sure. But I have to almost climb into the jars ti get any smell from them! I think it's a matter of the industry needing to meet a quota by harvesting plants before they go through a proper ripening stage.
People might be able to "prove" that defoliation increases yield, but I don't think yield should be the goal for most of us. I hear a lot of complaints from us older guys that the new weed just isn't as tasty as the older strains were. (I completely agree, btw!) I wonder if that might have something to do with the new standard that we have been introduced to via the industry.
Maybe we can improve upon flavors and terpenes by simply by applying small-batch grow standards and allowing the plants to do their thing in their own time...? I dunno...but that's what I'm going to focus on for awhile.