I wonder what opinions people here have on this 2D virtual world approach, compared to the full on bodysuit 3D VR-Goggles one.

2D works right now, has already proven itself to lend well to social interaction (Habbo, Club Penguin) and not to mention it works easily on mobile.

Is the ease-of-access enough of a headstart, or is it full immersion or bust?

People have been doing it since the early 1990s and it hasn't set the world on fire.

From time to time people trot out spatial metaphors as if they were fresh but it was a topic people were already making fun of in Byte magazine back in 1981. Microsoft Bob and similar things get laughed at whenever they are tried. Even the computer desktop is a big trashcan that gets cluttered with whatever junk installers want to put on it. (e.g. it's no accident that the only essential thing on the Windows desktop is the "Recycle Bin")

Cyberspace is hyperdimensional and has limitations entirely different from physical space. The one case for putting blinders on it and making it like physical space is that people might understand it a little better, but it's at the cost of losing all the magic.