The problem is while it's known what devices are in an Omnia - the low level information about those devices needed to write a driver for them isn't known.
If you know how to write device drivers and have the right information about the devices, then yes. It is very easy and rather quick to write a device driver.
But if you're like the Andromnia developers and don't have that information it's a much slower and more involved process of reverse engineering the device to be able to write and debug the driver. If you read the Andromnia forums you can see that there are a few people who have been working on setting up tools that help them probe the devices to do this reverse engineering. But it's no where near as quick and easy as writing from the docs.