Then they should've made that more clear, since the image we see of it is smaller than an Assimilation Cube.
If it was a "Class 1", then I'd think it was a powerful vessel. And "Tactical" is lesser than "Strategic", "Tactical" is for individual battles as compared to conquering civilizations.
Having hull armor doesn't mean anything for Trek ships, never has never will.
As it is, the Tactical Cube comes off as weaker than an Assimilation Cube.