Before Aristotle's complete works were translated into English in the early 20th century, the dominant trends in European and American philosophy were various offshoots of Kantianism and Humeanism, with a big smelly dose of Marxism thrown into the mix. There was logical positivism, existentialism, pragmatism, and, in ethics, utilitarianism.
Let's say that Kant didn't even live to present his developed system, but that the other players, in the hypothetical new context, remained more or less the same in their basic intellectual personalities. I think this still means we'd have had the massive movement among intellectuals toward socialism and pretty much the same disastrous consequences of such in the infamous experiments in Russia and elsewhere. What might have happened in America? Would the basic character of the Pragmatist movement be the same without Kant? The Rand-Peikoff analysis attributes much Kantian influence to Pragmatism, which supposedly adds to the villainy of Kant, but without Kant there would still have been Hume and Mill, and simple common sense tells you that, given the geographical and other limitations, American philosophy was more swiftly and directly influenced by English philosophy than by German philosophy. From Hume you get just as much a pragmatist mindset - arguably more - than you would from Kant. With Hume, there is just as much agnosticism about the "underlying character of reality" as there is in Kant. (This is one aspect in which Kantianism doesn't really even answer the Humean challenge; the concept of causation in the sense we really find interesting - i.e., an Aristotelian sense of human-independent natural necessity - is dispensed with by both thinkers.)
Kantianism never really caught on in America aside from ethics. (The leading "Kantian" of today in America is an ethicist, Harvard's Christine Korsgaard, and even she's not really a Kantian proper. There's too much Aristotelianism going on there keeping her basic moral picture sane, even if still deficient.) Humeanism, however, seems to be absolutely ingrained and dominant in the way recent academic philosophizing has been conducted in America. One thing I can say in Hume's defense is that at least he recognized what a dead-end his style of doing philosophy was, and that there was an irreconcilable gap between his philosophizing and his practical daily routine.
The mainstream American inherits this gap by dispensing with philosophy in favor of practicality. The mainstream of the academy has done extremely little to reconcile their style of doing philosophy with the concerns of the ordinary American. This has nothing to do with the fact of "specialization by experts" that ordinary Americans aren't equipped to be conversant with; rather, it is an extreme rift between the prevailing style of analytic philosophy and the needs of practical life. A certain novelist-philosopher did her damnedest to show that philosophy can be practical, and how it can be, with the academy doing just what by its nature would do - ignore, dismiss, scoff at, etc., this very attempt. It's "popular philosophy" and serious philosophy "is only done in journals." (How many people read philosophy journals? Why should they give a shit?) If "serious philosophy," meanwhile, is philosophy done in the manner of Hume and Kant, our culture faces grave perils.
Thank god, then, for Aristotle.
Were Aristotle around today (how many times will that phrase be used before this blog reaches its terminus?), he'd be conversant with the current mainstream - and he'd also overcome its limitations with his characteristic dialectical skill. So: How does Aristotle compare with Hume? Well, let's at least note this: Aristotle's approach to integration was such that he'd recognize the need to make philosophy practical, to go out of his way to align philosophy with the needs and concerns of the ordinary people. Maybe back in Greece, given its cultural and technological limitations, philosophy was effectively only for a relatively well-to-do or dedicated few. There is no such excuse for exclusivity in modern industrial society. A certain novelist-philosopher figured that out; an Aristotle today would do likewise, and applaud the efforts of that novelist-philosopher.
This raises a pretty striking point: Aristotle's response to Ayn Rand would be way, way different from what the Academy's response has been. An Aristotle worthy of his reputation would also be a staunch advocate of capitalism. That's prima facie evidence that the Academy has yet to come fully to grips with Aristotle's import to philosophy. (Sorry, being "one of the Big Three" is a deficient characterization. In the canon, there's the Philosopher, and then there's everyone else.) So, to answer the question: I don't think Aristotle would have been impressed much by Hume. He already contended with Hume-type foils back in his day.
To illustrate: Hume's dichotomous approach leads to an is-ought gap in meta-ethics. Aristotle would readily recognize the is-ought gap as based on a deficient or incomplete understanding of the facts. An Aristotelian - and commonsensical - understanding of goodness derives from the needs of living things, which are distinctively characterized by being "teleologically-ordered" systems, and which, by definition, meet those needs through the actualization of potentialities. It's quite irrelevant here what the original, ancient Aristotle had to say about the scope of teleology - and it's a base and ignoble response to Aristotle to criticize his conclusions while ignoring his methods. But that's exactly what countless people are conditioned to think when it comes to Aristotle. Time and time again I've personally touted the virtues of Aristotle, only to be met with the equation of Aristotle with his positions rather than his methods. This is quite pathological, and it would be interesting to come up with a complete accounting for this tendency, this awe-inspiring capacity for missing a point. (Or, if you like: "Awesomely committed to misconception," a phrase used by Michael Herr in reference to the clueless critics' and philistines' responses to Stanley Kubrick's cinematic genius.)
At least some academic philosophers haven't been so amateurish and point-missing, and, in fact, I find it plainly evident that the best and most sensible philosophers in the academy have strong Aristotelian (if not Randian) tendencies. It's the ones who take their methodological cues from the likes of Hume and Kant who are the problem. Even taking Rand out of the equation, the present situation in regard to Aristotle is pretty bad. Hell, anything short of full-on Aristotelian dominance in the Academy is bad. If/when empiricism can be reclaimed by Aristotelians from Hume and his descendents, and if/when eudaemonism rightly trounces its competitors in the field of ethics, some real progress might be made. That would necessarily bring Rand to greater prominence for those paying any attention to the true playing field, which would still leave the really obvious sick shit that's in need of fixing: the pervasive bias in political philosophy against the manifestly beneficial system of capitalism. I don't think Aristotle would approve of the vice going on there. Hell, even Hume and Kant would be appalled by it. Time for an overhaul there.
