there is no point of reference
SEVEN: This is a class 4 tactical vessel, heavily armed
Just so, there is nothing to reference the 'tactical cube" to. Heavily armed compared to what? A sea otter with a sharp rock? Given that the Voyager routinely and casually beats the crap of out of whatever Borg vessel they come across, not "heavily armed" in comparison to the Voyager.
The "heavily armed" label might simply be yet another of Seven's pro-Borg patriotic statements.