But consider most pagan mythology--their gods directly interact with the planet and the people on a daily basis.
Aren't prayer and worship ways that God and man can interact on a daily basis?
There are spirits in the trees, in the water, in the air, and in the mountains. A pagan (not necessarily a neo-pagan but your average superstitious country person from a few centuries ago certainly) might not be too surprised if while walking through a forest he entered a clearing and found a faun playing a flute and dancing or a group of dryads doing whatever it is that dryads do (I'm assuming they play pinochle).
I may be marginally insane for this, but that wouldn't surprise me much either. I'd probably spend more time trying to figure out what I was seeing than actually being shocked.
The Greeks thought that lightning was caused by Zeus and the sun moved thanks to Apollo. The Norse attributed earthquakes to Loki and thunder to Thor. Paganism as a religion is full of mystery and supernatural wonder as the gods and goddesses preside over the moral realms and go about their own business beyond the ken of man.
Many Christians also think God paints the sunset each night, or that he designs each snowflake seperately, and it's a rather common belief that God creates each person in the womb. There are other things that are explained that we often credit to God as well. It's not unusual to refer to natural disasters as "acts of God" either. I'm not quite sure what the difference is here, except maybe that we accept that more things are explainable by science.
Consider also Hinduism, which honors thousands of gods both major and minor. Each family might have its own set of gods that theoretically watch out for it in return for prayers, offerings, and devotion. Reincarnated souls can become divine, just as they can become common. Everything you see around you that lives has a soul just like yours and is worthy of honor.
Arguably, intercession of the saints in catholicism or the "dance" celebrated by orthodox churched could qualify as being similar here. There are differences, but I don't think that they make Christianity less involved with the supernatural.
Compared to these things, a created universe that pretty much runs itself seems kind of boring.
I like to think God is slightly more involved than that, but I could be wrong. I think it is quite fascinating though how much there is to discover about a universe that was created by a single supreme being.
Not to say that there's anything wrong with the way things are--I wouldn't trade our God for the all-too-human Greek gods, the Norse pantheon who lived under the shadow of their own demise, or the death-obsessed Egyptian deities.
Although it could be a fun trip for a day or two, I'd agree that I wouldn't want to live there.
But when crafting a world of wonder and fantasy where magic seems to seep from the seams of the earth and everything seems unreal and at the same time more real than reality, throwing in some magical beasts and allusions to pagan mythology seems perfectly natural and helps set the tone quite well.
I suppose, but it's easy enough to just to make stuff up. I don't see how that changes how much of the supernatural is in Christianity as compared to other religions.