Your answers are really valuable, although the climates are so different. After doing some research ( also in this forum ) i try to "convert" all this data to useful information for my location. Flow in Finland or cold U.S states is strong and short. Here there is available flow over 8-9 months but not strong. Hundreds of different plants gives nectar during this period, but not to much to harvest each.
I am almost sure that the KEY word is patience and harvest on the mid - end of this large season. I used queen excluders in 3 test hives to harvest "more" honey of the desired type by the clients ( spring - early summer light color ) . The result was that Queen Cells raised in all 3 hives above the excluder and also replacement cells in the brood box. 2 hives messed and 1 hive ready to harvest! It is so complicated, i think the ability of the queen is the factor that defines how many boxes are brood boxes. Its true, if there is brood in every box, then this colony needs more space, no ways to get rid of brood.This is definitely good, not trouble.
My conclusion is that excluders are not necessary but the "desired" type of honey is what... makes beekeepers trying to feet them in their operations.