My (current, tentative) understanding of this deep issue is that all mind-only teachings imply a perspective, which is generally not shared by most sentient beings. Why? Because part of the very process of individuation is the creation of the distinction of self and other. If you read developmental psychology, this happens in very early childhood, and is of course thereafter deeply ingrained in everything we think about the world. That is the origin of the 'self-and-other' division, which from a somatic perspective is completely necessary. But then it later forms the basis for the constant arising of 'me, mine, myself' and the consequent sense of division and otherness from everything around us.
Now, 'natural philosophy' takes this condition as its starting point; it assumes the reality of self-and-other, subject-and-object. And again, for the purposes of natural philosophy, which is concerned with analysing and mastering the forces of nature, that is a natural thing to do, there is nothing inherently the matter with doing that. But it looses sight of the crucial fact that reality is actually not something we're other to. There really is no such division, because there really is nobody standing outside of or apart from experience. Reality is actually totality, it is not actually divided between self-and-other, that division is first and foremost a reflex or a habit of thought. It is a necessary aspect of being in the world from the viewpoint of survival, but it is also an existential plight.
The most influential philosophy of mind in the West is representative realism of the kind developed by the British empirical philosophers. Long story short, this assumes the reality of the object or objective realm, of which the mind generates a facsimile, image or likeness. Then the understanding seems to be, that this image or likeness is continually enhanced by the progress of empiricism, which discloses more and more about reality and through which we gradually build up a more complete understanding. But the problem here is that the amount of scientific knowledge is already so vast that no one individual will ever know more than a narrow speciality. And there's also the 'fact-value' issue, which is that scientific analysis only deals with what is quantifiable, that it assumes that the objective realm is devoid of meaning, and so on. That is the origin of the whole materialist attitude in a nutshell; I have noticed that most people with a scientific materialist attitude (which is the predominant outlook in the secular west) assume that the phenomenal domain that is the object of scientific analysis, comprises the whole of reality; that is very much the empiricist understanding.
So - what the mind-only teaching is reminding us of, is that all we ever know of the world, even when mediated by scientific instruments, is still ultimately vikalpa. It is incorporated into our cognitive apparatus and then we make judgements about it. Obviously through scientific methodology humans have been able to realise great material power, but from the viewpoint of 'being in the word' that in itself is not necessarily beneficial (i.e. you have to put it to good use, and so on.) But the point I'm driving at, is that mind-only teachings come from those who really have seen through or beyond the 'illusion of otherness', they themselves understand the way the mind generates judgements which it then takes to be reality itself. So they have a different perspective or stand-point. And until we actually get to that stand-point - till we go 'through the looking glass' ourselves - we won't really understand what they're saying.
That is my current, tentative understanding of it. (For a very good comparison of Western idealist and Buddhist philosophy, have a look at Schopenhauer and Buddhism, Peter Abelson. It discusses many similar points. This blog post cross posted at DharmaWheel.)