But the Brian Herbert comparison just means you've never read anything Christopher Tolkien actually published (or you never attempted to read Brian Herbert's terrible terrible work). The only publication where Christopher Tolkien embellished or added to his father's writings was The Silmarillion, published under pressure from their publisher to get it out the door as soon as possible after his father's death and when he was younger (relatively) and less sure about his bargaining position to leave his father's work untouched. The added narrative was mostly connecting prose, meant to keep the story more coherent, and one full chapter replacing a version that was hopelessly out of date compared to the rest of the updates his father had added over decades. He's repeatedly expressed regret about changing The Silmarillion (including again in this article), and has even laid out exactly what he added to the story so you can mentally edit it out.
Every single other book (that would be 13 of them, I believe) that he's published has been literally a written guide to trying to piece together a chronological view of all the undated scraps of rough drafts and notes his father left behind. The only thing he adds are clearly delimited notes about why he thinks some scrap came next and summaries about how some minor change made elsewhere suddenly made ripples of changes through future drafts of other sections, which he then proceeds to include verbatim.
In other words, there's no way to get less respectful of his father's work, short of leaving it unpublished. Again, he can be called many things (he really does seem to be like a total jerk, and there's no way any adaptation would have pleased him, even a word-for-word dramatic reading), but comparing him to Brian Herbert and what he did with Dune is beyond the pale.
Yes, Brian Herbert's work is just that bad :)