Transpiration is the flow of water through the plant and evaporation.I must not be understanding something. Transpiration is a natural function, you speak of it as a negative thing, or a thing to be managed. Transpiration is the final gasp of water as it moves through the plant, I am curious as to what you propose here.
A transpiration issue is when something is affecting that flow of water through the plant negatively. Which can inhibit nutrient uptake, transportation of nutrients/sugars etc, reduce the plants ability to cool itself and process light energy etc.
Yes a transpiration issue is negative as it's vital.
Yes transpiration should be managed for plant temps, nutrient/water uptake and water stress, utilization of co2 etc.
Root issues, temp, humidity, light, co2, o2, wind, salinity and pretty much all things that affect the plant absolutely effect the transpiration rates. It absolutely needs to be managed. It's a natural and vital function that can cause a host of issues if not managed. Not just the last grap of water through the plant.