I would think the very layout of Bytopia itself would be interesting, regarding finding anything interesting there. *shrug* And well, you don't find anything interesting there? Make it up.
The thing I don't get with the hatred of the Great Wheel is that nobody is forcing you to use it if you don't like it. You can homebrew your own cosmology if you want. You can just never go to the planes if you want.
Hell, you can use the wheel and make up your own stuff for it. Want the PCs to go to the first layer of Aborea, but you don't want to go to Arvandor or Mount Olympus or the Gilded Hall? Hey, you're in luck, there's an infinite amount of the first layer of Aborea that isn't any of those places. Come up with your own, you've got a framework to work from, run with it.
Don't want to stop through Sigil? Don't. The PCs find a portal that goes directly to whatever plane you want them to go to, or they Plane Shift there and back out again. No need for Sigil if you don't want it. Do want to use Sigil but don't want to use Cant? Don't. Don't want to have the players talk to a Dabus and make up rebuses? Don't have them run into one, or have it ignore them. It has better things to do.
(Personally I like Cant and most of it you can more or less figure out from context when it's used in the setting material, but YMMV, of course. My current character, in fact, who's a prime who spent a few years on the planes and is now back in his home prime where most people have never even heard of them, slips into using it whenever he's annoyed, specifically *because* he knows nobody around him has any idea what he's rattling his bone-box about. >D)
But yeah. If you don't like the Great Wheel, make your own cosmology. If you only need a little bit of cosmology, why not just use a bit of the wheel, one of the parts that gets your juices flowing, and either draw on something that was described in the Planescape setting or just use the general gist of the plane to make up your own location there? So Mount Celestia bores you; that's OK, I don't like it much either. Don't go there. You are not under any pressure to visit all 38 planes of existence. Unless of course you're actually running a planar/actual Planescape game and that's the party's goal, in which case, great, run with it. Otherwise, if you find x plane boring, you merely need not go there. Go somewhere you do find interesting. If you don't want to deal with philosophical or moral issues, don't.
And even if it's not 'interesting' or a place you'd ever go... That's not really a justification for it to not be there. Some small farming village is rarely interesting or somewhere you'd deliberately go. It's there anyway. It serves a purpose in the world. I'd probably never go to Mount Celestia. Doesn't mean it needs to stop existing or that it's redundant, just because I don't find it interesting. Same for the Quasielemental Plane of Salt. Just because I'm not likely to go there doesn't mean it doesn't fill a niche. You need salt to live, right?
It fills in the planar 'world', just as the little villages and cities you've never been to and never will go to on other continents fill the prime world in.
It's like having a god of Agriculture. Is an adventurer going to use it? Generally not. Would there be one anyway? Well, yes. Do the elves *need* the ten or so gods they tend to have? Well, yes. What's Hanali Celanil got that Aphrodite or Sune or whoever doesn't have? She's elven. For elves, this is important. She's the goddess of *Elven* love, not human. Would you want to worship an elven love goddess rather than a human one?
Same thing with the planes, really.
I'll save final judgement on the 4e cosmology until after I've gotten to read the 4e MotP and get a better handle on it, but so far just as I don't like the default pantheon or the changes to the FR pantheons, I'm not feeling it that much. Chances are good if I actually get around to DMing that game I want to get going I'm going to just dump the 4e cosmology in favour of the Wheel, just like I'll be dumping the 4e pantheon.
But seriously... You've got 38 infinite planes, quite a few of them with multiple infinite layers, and people can't think of anywhere they want to go? Then where are they planning on going in 4e's cosmology that's so vastly different from this?