I think the worst decision was to add individuality to the Borg.
It's done over and over again (in film and literature). First add an implacable (and therefore interesting) threat. Then give it a central processor, or in this case a Queen, and you instantly know the snake now has a head you can cut off.
The interesting foe instantly becomes normal, mundane, defeatable through regular means...
I loved the Borg as presented up until 1996; pre First Contact. Using the captains of your enemy as ultimately disposable commanders is genius.
Growing a head that allows your enemies to kill all of you with a single stroke, OTOH, is hackneyed lazy tired writing.