I'm not in a position to draw any definitive conclusion of features and distinctive characteristics of Western Buddhism. But in my impression, one of the most striking features or tendencies found in Western Buddhism seems to be its rejection of sharp and clear-cut dichotomy of ordained Buddhist monk and lay Buddhist.

Buddha endorsed the Buddhist monkhood/aka priestly class because only his former ascetic friends seemed interested in what he was teaching at first. He wasn't all that convinced he should be teaching at all anyway. But supported by the original Sangha in Northern India/Nepal he apparently decided to go that route; maybe for lack of any better ideas coming to fruition. He is reported to have said, that in about something like 500 years from his times his teachings would die out (most probably from attrition I gather).

Speaking strictly for myself, I believe that came to pass. At the time of the first or second synod of Buddhist leadership, some 400-500 years later, what happened was an apostasy of some sort or another (maybe only minor but an apostasy nonetheless) and from which comes the Pali "Canon" and the Theravada Buddhist religion itself as it exists still today. This is the crucial point where the ordination of the monk/priestly caste, and the laity, seem to have diverged into perpetuity—it's also true for "Buddhism" itself, the divergence. It's a natural course of events that seems to happen in all religions at some varied but very specific point—that is if you study comparative religions; many Buddhists don't because it causes too many conflicts of faith.

It was probably to be expected that a divergent philosophy would be established in Ceylon 500 years past Buddha's time, and Buddha knew it would come eventually. His guess was pretty accurate too, in my view. It's really where Buddhism devolved from a viable way to deal with multiple Hindu religions, and into a quasi-religion of its own right. Not too many Buddhist schools of thought have been able to agree on many essential matters ever since—hence the divergence that we still see. Many here will say I'm full of shit too. But to me the divergent apostasy that occurred is fairly obvious, albeit I have long since stopped trying to convince anyone of this obvious transparent fact of life.

Buddhism (per-se) is way ahead of most other religions when it comes to separating the reality-based wheat from the chafe. ..And why I still ascribe to it, although not in the overt religious way like so many other Buddhists try to do. I don't "take refuge in the Buddha" as some will say; just his teaching.

In Zen, the prevailing concept is to face away from too much institutionalization of Buddhism, and the Buddhist canon; Pali or Sanskrit. But in Zen they do the opposite fairly often too, reading and chanting, etc.. I think it's to scratch an itch of those who feel a need to be at least quasi-religious or to deeply study something. Besides, study and chanting and meditation have a real purpose. The whole Buddhist canon in parts is probably just arcane and antiquated ideas, which are based on Buddhism, but not on real Buddhism (save in name only)—except the parts that were really uttered by Buddha—that's impossible to discern though. These things got added in piece-meal fashion over 500 years of oral recitation of the Buddhist canon, before being recorded and set to writing. Those who follow Theravada lore do it in so minute detail that they seem to be lost (at least to me) not seeing the forest for the trees. Zen is the counter argument in Buddhism to the Theravada schools. Zen and those schools closely aligned with it are probably more in keeping with what Buddha had in mind from the very first. But he had limits (being fully human). He could only work with what he had at his disposal; those monks that were of the original Sangha, the real true forest tradition. What came eventually after Buddha was a trend to drift away from Buddha’s examples and teachings—although Thai Theravada Buddhism of that offshoot called the forest tradition, may be a drift back again (it's hard to say though).

Try to tell any of this to some members of an order of Buddhist monks bent on the idea that their way is all there possibly is. It gets frustrating to say the least, unless you in some small way divorce yourself from thinking of other "orthodox" schools as truly orthodox; but just simple conservative/fundamentalist offshoots of a true original.

However, it has never been put into practice widely and actively by lay Buddhists until the emergency of the so-called Western Buddhism.

Exactly!

If that is really the case, that is a good thing for Buddhism and Western Buddhism is on the right track.

Yes of course. Try reading some of the writing of Stephan Batchelor, a former Tibetan monk, then Zen/Chan monk, and then later a married lay scholar on Buddhism. He tries to simplify Buddhism in places where lay people can enjoy the same stature as Buddhist monks do. But he catches lots of flak for it—even to be called a denier of Buddha, or of reincarnation. So-called reincarnation is a thorny rose that is best left alone anyway, but people strongly opposed to Bacthelor say his ideas deny reincarnation. He says otherwise, but we don't or we can't understand it intellectually, and it's a mute point anyway you want to look at it. ..And that makes a lot of sense to me.

Alternately—not to flatly deny all existing samples of Buddhism besides the Zen family—all of the others lead to the same place anyway, eventually. The true idea is to forget what you might know through learning, in favor of what you already know somewhat unconsciously—but also have extreme trouble understanding and articulating, so that others can grasp your meaning. In other words in Zen just live your life, do your best, the rest will follow—which is exactly what the laity is all about in the first place, anywhere you want to look at it and for anyone truly trying.

There is a saying that travels around in AA circles that says: 'bring the body and the mind will follow.' I can't imagine where that saying originated, but I'd be willing to put money on the logic that it came out of Buddhism and Zen/Chan schools to be more exact. I think it brings it all full circle too. Buddha knew this conceptual idea and he was merely trying to attract bodies into his immediate circle (of monks) in order to get their minds to follow. But it got lost when some later followers had supplementary ideas that the "awakening" as experienced by Buddha was only available to the community of monks at large—and supposedly established only by Buddha himself. Over the centuries logical fallacy on top of logical fallacy just proliferated, until Buddhism became the multi-denominational religion we now have. Zen and similar schools try to counter this but with only mild success, I think. It comes down to an individual endeavor anyway you cut it; in western Buddhism that concept has found very fertile soil and has taken strong root.