Does Devarim prove TMS false?

One of the problems in discussing the DH is that no matter how clear the contradictions, duplications and textual divisions in the text might be, you can be sure that some highly imaginative Rishon, Acharon or latter day Parshan has created a beautiful peshat which ties it all together, and also highlites various common themes, word plays and all sorts of things. I remember Hirhurim doing this with Parshat Noach, showing how certain words were repeated a certain number of times, even though according to the DH we have two different texts spliced together. So how to we address this? I see a few possible approaches:

1. Admit that as much as the DH methodology provides good argument for multiple authorship, this 'Parshanut' methodology provides good arguments in the opposite direction.

2. Assume that the Redactor was a genius at splicing things together to create these kind of wordplays, lessons, common themes or whatever. This then begs the question of why would he do that, and leave so many contradictions still in the text.

3. Say that this Parshanut is all nonsense, and that anyone could take any sufficiently complex text and produce all sorts of wonderful drush on it. And even more than that, the fact that the Torah is a bunch of spliced together documents actually makes it easier to produce drushim, because it's such a mess. Jacques Berlinerbrau advances this theory.

So what do I think? Rationally, I think 3 is probably true, but I must admit that when someone does produce a particularly good drush, it makes me think twice. Could it really all be such a co-incidence?

Anyways, david a says the following:

One does not need a complex DH to conclude multiple authorship. Any reasonable objective person would come to the realization that there is no way Devarim was authored by the same person as the rest of the wilderness portion of the Torah.

Aside from the obvious difference in language, style and terminologies, the author of Devarim had different hashkofot (eg. His views on the relation to God, reward & punishment, Kapporah, political views, attitude to the kehuna, and other ideas) and he promulgated many laws completely different from the those expounded by the rest of chumash (eg. yom tov, maaser, matnas kehuna, bechor, shmittah, he likely didn’t know about yom kippur, and maybe his view of shabbos was less strict, etc,.) Also, his icons were different. No ohel mo-ed and no adulation of the kehuna, particularly aaron). In addition, every single one of the retold narratives in Deut 1-11 has enough differences and contradictions to the corresponding incident to make a compelling argument that the “moshe” of Devarim could not have been the same “moshe” of the rest of chumash.

I constantly tell people if you really want to appreciate this for yourself, do the exercise..compare the literal text in terms of the narratives, the laws and hashkofot with the rest of chumash. It’s a long exercise but to me it was a clincher.

OK, so let's do it. We'll go thru Devarim and see what the differences to the rest of the Torah are. Then we'll look at all the droshos and parshanut on these differences, and weigh up each against the other to reach a conclusion.

And then all the skeptics will say 'See!', and all the believers will say 'See!', and no progress will be made. Oh well.

Course none of this says anything about whether God wrote the Torah. I just assume He didn't, since we have no evidence of God writing any books, or even existing, so it's a no brainer really.