I'll take a crack at this one, inspite of what might fulsomely be termed my manifold ignorance of Deleuze.

Wittgenstein once remarked that Hegel seemed always to be trying to show that things that were seemingly different were really the same, identical, whereas he, W., was trying to show that things that were apparently the same were, in fact, quite different. (One of his proposed epitaphs was from "The Tempest": "I'll show you the differences.") Hence, "the cat is on the mat" and "he is in pain" are syntactically similar, but "functionally" very different: he is not "in" pain, nor is pain "in" him, in the way that the cat is on the mat.

On the other hand, the basis or root of Hegelian difference is the distinction between consciousness and world: consciousness can only exist if it distinguishes itself from the world, (hence constitutes itself as "negative"), by constituting a self-relation, which, by the very same token, must relate itself to an "other", which is different from itself, which would be the world in which and from which consciousness is distinguished. To be sure, Hegel is guilty of enormous hyperbole, and his basic project of establishing a rational objective realism by recourse to absolute idealism, whereby the full and complete adequacy of our knowledge of the world as a whole would be demonstrated or guaranteed by an ultimate "aufhebung" of the difference/opposition between appearance and essence, repeatedly begs the question of just who or what is doing the constituting, as well as, just what is being "guaranteed" in terms of how the world is actually layed out amongst its constituent "moments" or elements, conscious or not.

But leaving aside the tremendous transformation of the classical tradition of metaphysics involved and the projected aim of critically saving the Enlightenment from itself through the "aufhebung" of its "diremptions" or dilemmas, the Hegelian "absolute", as infintite self-reference in otherness, for all that it absorbs all existent particulars into the ultimate "identity" of the world-process, could be seen as asking the question: how could there be (meaningful) difference without self-relation? (The question would presumably be intended with transcendental force, that is, as claiming things are not otherwise conceivable).

The Wittgensteinian rejoinder would be: how could consciousness ever be "identical" with the world, if consciousness can only meaningfully exist or signify as the production/awareness of differences, as its distinguishing activity itself? (Presumably that question has de-transcendentalizing force, as denying any "absolute" conceptual necessity outside of our involvements with practices and relationships within a "form of life" or world.)

Now Deleuze, I take it, is operating "beyond" the purview of either of these two gentlemen, and is rejecting not just any "aufhebung", but any appeal to anything pre-existent, as constituting or enabling a rational order to the world, "outside" of sheer particular existents themselves qua particular. Further, I would guess that what he's after is something like the definition of information as "the smallest difference that makes a difference". (And there's more than a bit to that; our empirical sensory experience is not organized by transcendental "mind" or "pure thought", but by evolved neural processes that form an informational matrix prior to any conscious experience or consequential thought or behavior.) Hence he would want to lay claim to a sheerly differentiating difference, to difference as (the process of) differentiation.

But I would question the intelligibility of such a notion of difference without ipseity, for in order for a difference to make a difference, there has to be a context in which it does so, and thus some prior organization or, better, interaction of organizations that sets up that context. That needn't involve consciousness at all, nor any pre-existent "rational" order, but, since the emergence or "production" of novelty does not occur ex nihilo, but rather through the conversion of "noise" into new information/organization, difference can not really be conceived without an element of self-relation at its root, if only, as it were, formally, and that involves, in turn, a stepping outside of the sheer immanence of particular existents, if only to establish the sheer particularity of an existent, in contrast to some putative undifferentiated matrix.

Beyond that specific criticism, though, I suppose it all comes down to a matter of taste, or, perhaps better, tact. For, while I think it's legitimate and reasonable to question the non-rationality that subtends any claim to rationality or rational order, as well as, to criticize any self-limitations or self-reifications that might be involved in such claims, I don't think that considerations of rational orderings are dispensible, since, in contrast apparently with some of its critics, I think rationality is itself precarious and not to be identified in any undifferentiated way with the forces of oppression. And whereas I wouldn't want by any means to resurrect the full monstrosity of Hegelian idealism and its all too "optimistic" identities, and I think I grasp some of the latter-day French objection to the "aufhebung", whether conceived conceptually or existentially-historically, as overriding falsely or wrongly the irreducible particularity of existences, the new Nietzschean dawn heralded under the banner of "antihumanism" might amount to an even worse overriding of such precarious attainments of rationality as we can maintain.

Perhaps the paradox in the matter is this: "we moderns' really do believe in something like what Hegel attributes to us, the progressive attainment of self-conscious freedom through the intersubjectively mediated recognition of the world as an objective order of rational truths. At the same time, on the evidence of modern history, the very ground of Hegel's unprecedently worldly metaphysics, with all its regressions and catastrophes, we don't believe it. Yet, when we struggle to make sense of the derelictions of that history and its contemporary extensions, we are thrown back on what we do/don't believe. We are caught in an all-but-inevitable oscillation between a critical repudiation and a critical renewal of an impossible dialectic.