When Playing or DMing, I have always found it more enjoyable and useful respectivley to have the details of the planes obfuscated. I hold fast to them when running in published settings (which will most likely come out with planar books after the switch), but for home games, I like the etherial (Not the planar meaning) nature to ease the use of the inhabitants in wider than traditional roles.
What I mean to say is that no barrier will exist unless the crusty old players (Myself included) make it themselves. Like Planescape in 3e, it will be a small task to assemble the old fluff extrapolated from the new.