Actually, I think the Sphere from 'Drone' was the one that adapted way too fast to Voyager's attempt at disabling it's engines.
It was nothing more than a gimmick to emulate the 'danger' the Borg presented so that 'One' could sacrifice himself to save the ship asap.
I would at least think the enhancements 'One' did would give the Sphere a pause.
As for Voyager's assault at the Tactical cube... Voyager was barely able to hold on in a firefight with it, plus the cube didn't really see it as a real threat.
And why would it?
Even with the modifications from 'One' and 7 of 9 on-board, Voyager was no match for it - but it WAS able to hold on it's own for a small amount of time (a few minutes) before it retreated - although the queen could have been toying with it for the sake of it.
Plus we saw just how fast the shields (in certain areas) were pierced by the Tactical cube.
And even with the 'liberated sphere', the Cube was receiving more damage, but it was still in a winning position.
The Queen merely destroyed the cube out of pure spite for Janeway's trickery - which was way too emotional on her part.