To say a fullback must be a ball player is misguided, especially where the incumbent Australian fullback (Slater) isn't.
The Broncos structure, since the glory days of K.Hunt and Lockyer, requires a ball playing fullback. Lockyer, Norman, Wallace, Hunt, Macca, Hodges even are all ingrained with the low percentage play, build for a second man sweep to the fullback inside our 20 way of playing.
That's our structure and our shape on the pitch.
Hoffman is average at a ball playing fullback structure.
Now you can change the structure, or change Hoffman. The latter is much easier.
Given the structure hasn't brought a premiership in 8 years, perhaps it's not Hoffman that's the problem.