So we are talking about a custom debugging tool here and not something that would actually be used in the editor. Sounds like overkill to me. You can check the correctness of the individual parts of the model onces the respective views are implemented.
But I don't know how much work such a custom debugging tool actually would be in Qt. Might be trivial after all. So if you really want to do it, go ahead. But you should make sure that it is properly separated from the real GUI, because there we definitely don't want any treeviews (individual filters and maybe one more case not related to ESX records being the only exceptions I can think of). We probably don't want to have this debugging treeview in the release build.