By equating Rangtong with a Shentong-created straw-man, do you mean that the so-called 'Rangtong' is simply Madhyamaka properly understood, or do you mean that the two views are in fact complementary and not contrasting?
I mean that there is no rang stong at all from a Madhyamaka perspective: Nāgārjuna states:
If there were something subtle not empty, there would be something subtle to be empty,
as there is nothing not empty, where is there something to be empty?
I mean that there is no rang stong at all, apart from what the gzhan stong pas have fabricated.
The gzhan stong controversy arose out of a need by Tibetans to reconcile the five treatises of Maitreya with Nāgārjuna's Collection of Reasoning based upon the erroneous historical idea that the five treatises were authored by the bodhisattva Maitreya rather than a human being (who incidentally was probably Asanga's teacher).
In my opinion, the five treatises were a collection of texts meant to explicate the three main thrusts of Indian Mahāyāna sutras, Prajñāpāramita, Tathāgatagarbha, and Yogacāra. Four of the five are devoted to these three topics independently, with the Abhisamaya-alaṃkara devoted to Prajñāpāramita; Uttaratantra devoted to Tathāgatagarbha; and the two Vibhangas devoted to Yogacāra . The last, the Sutra-alaṃkara is an attempt to unify the thought of these three main trends in Mahāyāna into a single whole, from a Yogacara perspective.
When these treatises arrived in Tibetan, at the same time, a text attributed tothe original Bhavaviveka, but probably by a later Bhavaviveka, translated under Atisha's encouragement, called Tarkajvala, presented the broad outline of what we know call today " the four tenet systems".
In this text, the three own natures and so on were presented in a very specific way from a Madhyamaka perspective and labelled "cittamatra".
So, the gzhan stong controversy (with additional input from Vajrayāna exegesis based on a certain way of understand the three bodhisattva commentaries) is about reconciling Madhyamaka with Yogacara.
Personally, I see no need to attempt to reconcile Madhyamaka and Yogacara. Madhyamaka is the pinnacle of sutra explication. But Tibetans did and still seem to need to do so, and they have passed on this need to their students.
But from my perspective, one cannot go beyond freedom from extremes.