Well, there are a couple problems with that. First, there are already a few PCs whose gods speak to them in some form or another, and second, I would prefer to not remove options from potential players unless we need to.
The existence of devas sent from the gods does not necessarily mean that people now have no doubt of the gods' existence - they might just be exceedingly rare. So rare, in fact, that perhaps the only such devas that exist in the setting are those that happen to be PCs (note that I'm not counting devas from "Devaland" here, because they probably aren't sent directly from their gods

). And, actually, even the fact that "Devaland" exists can be enough for people to doubt the divine origin of devas that just appear, if that's what you want.
From your example with the dwarves, I think it's important to remember that the 'traditional' Mykonos' Sanctuary dwarves and the Valley of Bone dwarves are actually two separate and distinct groups - neither has any real ties to the other, besides the fact that they're the same race. I think that if you tell people that every deva
has to have come from Devaland, they won't like that very much. There should be at least two origins for devas that are entirely separate from each other, so that people who don't like one of the origins have something to work with. And a lot of potential players will want something like the PHB2 fluff, because that's the ideas they've had for their deva characters.
About the gods being hands-off, maybe I'm just bringing the Greek mythology base too much into L4W here, but they were pretty hands-on, but mainly with bigger world events. (That's also why there's tons of demigods in Greek mythology, because the Greeks didn't really have sexual morals, and neither did a lot of their Gods.) Now, that doesn't necessarily lead to a Forgotten Realms-like setting, because the Greek gods are ambiguous in a different way - they're not absolute on the good/evil scale. They pretty much act like super powerful humans (and less than mature at times), changing their minds and changing sides often. I think this could be a really cool element to bring into L4W; say, in mid-paragon, the gods might start showing up, but they might be on your side or they might be with your enemies, and they might even switch halfway through an adventure. And, if there's a god showing up on your side, it's pretty much guaranteed that there will be a god showing up on the other side, unless you're just fighting monsters. But even then, most people (like 99.99%) are never ever going to see one of the gods. And most of the time that the gods do actually roam the world, they disguise themselves as normal people. They were hands-on, but to most people they still felt distant, because they never saw the hands. Am I making sense?
One last though - if you can bring back the dead by petitioning Lauto, and there are people who can invoke their god's power in a very real, physical sense, and there are people who can hear the voice of their gods in their heads, how can people possibly deny that there are no gods? Only if they've never seen or heard of these things could I believe that, or they're super-paranoid conspiracy theorists who think it's all a conspiracy and
they are out to get them
[/rant]
