"The D&D cosmology — largely unchanged since 1st Edition — is receiving its share of scrutiny as well. We're making revisions to the cosmology so that the planes work better as adventure sites. Case in point, the individual Elemental Planes (as decribed in 2E and 3E) aren't the most interesting adventure locations; their sheer inhospitability, vastness, and uniformity discourages exploration, and the creatures that dwell there are predictable and easy to thwart if you're packing the right spells. (Of course, these planes don't hold a candle to 2E's hilarious Plane of Vacuum, which is truly the antithesis of fun.) In the Wizards Presents: Worlds and Monsters book, we'll present in more detail 4th Edition's alternative to the Elemental Planes of Water, Fire, Earth, and Air. My hope is that the cosmological changes will excite players and actually encourage DMs to set adventures in these far-flung locales."
I find some very bad logic in this quote. The planes are inhospitable and discourage exploration, yet the creatures are predictable and easy to thwart. To me this doesn't make much sense. I believe we call this home field advantage. It's the same way you take a penalty turning undead in an defiled area. Call me crazy, but I don't expect my ray of frost to work well in a plane of fire.
I also wave the BS flag. First of all you need to be pretty high level to get to the outer planes (I exclude Planescape which is a specific campaign world). We know the current sweet spot of DND is not typically past 12th level and many groups quit playing after this. Therefore I would argue most groups or players have not even had the opportunity to travel to the elemental planes. I would argue that most people posting haven't even attempted to adventure in them. I also realize that this does not prevent you from wanting them changed in an upcoming edition.
To me the planes should be alien, inhospitable, and elementals in their home world should be near indestructible. The reason is that when these creatures travel to the prime material plane, they should be feared. In my world and most DND players' world, mortals don't mix with the Gods. I certainly don't want my low level or mid level players adventuring there.
The planes should be a paragraph in the core rules. The should remain much as they have been in previous editions. Those that do run campaigns at high levels and want to send PCs to the elemental planes can generate the worlds in whatever fashion they like.
It bothers me that this is something the designers are even concerned with. I have never sat around and had a conversation with any of my four previous game groups over 20+ years and said that the planes need to be altered. There are so many other improvements to be made or detailed. I don't think the DND community is clamoring for this as there hasn't been a big outcry in the past.
DND is like a house built on a foundation. You call them sacred cows if you will. Start knocking down too many struts and the house collapses. When it's rebuilt, it may not be the place you used to call home.