I can imagine that Dutch Safety Board may more trust CVR than voice records from Ukrainian ATC.
Well, you'd think so. They would have to match, of course.
Significant in the report is that the say Ukrainian crash investigators did spend a few hours at the site in the first days. Unknown to anyone. Maybe the didn't tell the "guards" who they are.
So they probably would have obtained the ATC tapes. Ukraine is part of the investigation team, so they wold have taken the ATC tapes with them, I assume. It is not likely to show anything relevant, except perhaps settle the conspiracy about MH17 being deliberately vectored into a trap.
Under Dutch law they won't be publishing the whole CVR transcript, unlike American investigations.