Both my Hollowbody ii and my 594 Hollowbody ii (as seen in my profile pic) share the same pick-ups - the 58/15 LT's and whilst they do have slight differences by design, like the block inside, the scale length and neck carve, mine also differ in finish as well as the 594 has had the TCI process applied too and even the different bridge type (wrap around with Piezo vs ToM style) can all have some impact on tone. The Hollowbody ii may have a smaller block but does have a Piezo and pre-amp inside too.
With all that said, they are quite similar - similar enough that if you were thinking of buying based purely on sound, I think it wouldn't make a difference. There are subtle differences but with so many little differences, I cannot say that the 'block' makes a difference or its a result of the TCI process, maybe the difference is finish or scale length, type of bridge or having a pre-amp inside - but overall, they are close enough that I don't need to pick up one over the other based on tone.
What I mean by that is that the features and neck shape are more of a factor than the differences in sound. If you prefer to have individual coil splits to a Piezo, then it makes much more sense to go with the 594 - regardless of whether the 'block' is bigger or not. For me, I don't pick up one or the other because of the sound, both are completely interchangeable for the most part and sound 'close' enough to each other for me that the tone doesn't factor into my decision which one I pick up - its more likely to come down to whether I want/need coil splits or Piezo and both are exceptional guitars so can't go wrong with either or, like I have, with both!