I don't think they intentionally tried to weaken the Borg.
I think the concept the writers had Voyager exploring was the idea Lt. Eddington started in DS9, about how the Federation isn't much different than the Borg. Voyager was more about humanitizing the Borg and showing that they aren't one big willing, functioning unit but rather billions or people trapped and enslaved by one mind, the Queen. Voyager was much about how Federation life relies allot on technology, Borg life relies allot on technology. Was Admiral Janeway in "Endgame" much different than the Borg Queen in "Unimatrix Zero" when it came to protecting and saving her "family"?
I think this is the point on why we had to encounter and explore the Borg way of life so much on Voyager.