I never found anything particularly forced about the Great Wheel.
And aren't Bright Shiny Reflection and Dark Grimy Reflection, both of which have their own sodding Underdark more of the same horrific forced symmetry, even more so since there wasn't all that much symmetrical about say, Arborea vs. Mt. Celestia other than both having really big mountains and being good-aligned? It's not any more clevar or funneh than the Wheel was.
And sure, you may not have ever run into a use for the Quasielemental Plane of Vacuum and you would have needed tons of magic to go there if you did have a use for it - But it *wasn't intended for you*. The elemental planes were not created with mortals in mind. You are not naturally intended to go there, and this is a *good* thing.
See, I don't like the idea that the entire multiverse must be relatively safe for adventuring and especially not for habitation. That's a load of dingoes' kidneys. The multiverse wasn't created for mortals. The gods/whatever forces created and shaped it did not make it for you. There's a Quasielemental Plane of Vacuum because it fills a role in the multiverse that is more or less necessary, not because it's a good adventuring spot. Various planes can and *should* be utterly useless to almost the entire population of the multiverse, because they should exist as something besides just Nifty Adventure Locale #83,892. The multiverse does not revolve solely around mortals. It shouldn't.
So bring on all those 'useless', 'boring' planes of vacuum and radiance and positive energy and the infinite deathtraps of the the Abyss and all the gloriously inhospitable places that will kill you instantly, because they make for a better cosmology. They fill their role, a role that is bigger than you and has nothing to do with you and does not give a wet slap about you, and you will never be able to confront them without more magic than you can shake a Wand of Magic Missile at protecting you.
And this is *awesome*. This is great and wonderful and really gets the juices going as to just how utterly small and inconsequential you are in a multiverse composed of an infinity of infinities, an infinite number of which are utterly inhospitable to your form of life. So much of the multiverse you can't even touch, and yet look at how much of a difference you're able to make on your smaller, mortal scale through your actions. Save a village, save a continent, save an entire crystal sphere or even manage to prevent the destruction of a layer of a plane and it means nothing to the multiverse, but look at the difference it makes to the things that *you* actually care about. The meaning of it all? There isn't one. The multiverse is incomprehensibly massive and doesn't care about you or your actions. Looking for meaning or use or reason in it is utterly futile. So you make your own meaning and find it and yourself.
*That* is what I want from cosmology design and planar adventure. Not 'Oh look here is another dangerous but ultimately relatively safe parallel plane or tiny astral dominion, let us run around in it freely and have a good time and eventually we shall become masters of the universe'.
YMMV, of course. But the 4e cosmology leaves me yawning. Gimme back my 'useless' symmetry. (Though for fun I've pondered the idea of the wheel containing no set number of chaotic planes, the number of which in existence at any given moment would vary depending on whatever factors it happened to depend on at any given moment. Today there's five planes of chaos. Yesterday there were thirteen. Tommorow, who knows.)
