Well, there are two very important reasons why Levitation was not included in Oblivion and Skyrim. And this is not just because the cities need to be contained in their own cells, which is the main reason for it not being included. I was hoping someone would have come up with this by now. In Oblivion, it would have removed the challenges of the Oblivion Gates, as you could float up to the doors you were intended to fight your way to. In Skyrim, it would pretty much take away half the dragon battle challenges, which is damage the dragon while it is in flight and to get it to land. People said Oblivion Gates and Dragons are too easy now, with Levitation, there would be even less of challenge.
First, I'd say that levitation would barely help in a dragon battle at all. Levitation is slow, dragons are zipping all over the place. It'd barely be any more effective than fighting a dragon on the ground. Perhaps even more difficult as you'd have to concentrate both on fighting the dragon and maintaining levitation lest it run out and you fall to your death.
Even assuming it would be unbalanced, why are level design and encounter problems dumped on things like levitation? I mean, you were just arguing that levitation shouldn't be in Skyrim, because nothing is designed around accommodating levitation. Why then would we compare Skyrim designed with levitation in mind to Skyrim designed without levitation in mind, but the devs shoehorned it in anyway? If the devs cannot think of creative ways to maintain challenge while including something as straightforward as levitation, perhaps the problem is with their design skills. Enemies with range attack options, enemies who dispell your levitation (this could result in death from the fall), enemies who can fly or use levitation themselves, reduce the speed of levitation, make the maximum levitation height a result of your skill level or spell level (low level means hovering five feet off the ground, beneficial for crossing gaps, not for avoiding enemies), remove combat options while levitating (say the concentration cost is too great to focus on other things while levitating), etc. Any of the solutions could fix the problems you're seeing here.
I'd also argue that some areas
should be a breeze for certain characters. If the challenge is fighting two dozen enemies, a warrior will obviously chop their way through with ease in comparison to an unarmored thief or mage. Why then, shouldn't a mage with levitation have an easier time when the challenge is to ascend to the top of some structure? That's not a broken mechanic or avoiding gameplay. That
is gameplay. That's playing to your character's strengths, that's using your skills and the environment to your advantage. It's no different than a thief sneaking past enemies instead of fighting them head on.
However, I can understand why people want it, what I can't understand is why people think it is needed in the game. There is no game related reason for Leviation in Skyrim as there is no place you need to float to or around in this game. One poster said that views from up on high are incredible. Well, yes they are, but I can climb up to all kinds of places to have a nice view, I don't need to float up there.
Nothing is "necessary". Beth could easily leave out whole races and still produce a game as large as Skyrim. It doesn't mean that it's a good decision or that it shouldn't be changed