I heard it in an interview, I forget which one.
I don't recall hearing that anywhere, the only things I recall hearing about leveling is that since classes are removed, all skills contribute to leveling up, but the higher a skill's level, the more it contributes, so you'll level faster if you specialize, and that instead of the attributes we're familiar with, upon leveling up you get to directly increase your health, magicka and stamina, and can choose a perk, but of course, I could have missed something.
Though honestly, I don't care too much either way about whether or not sleeping to level up is still in, it was a reletively pointless but ultimately quite harmless mechanic, on the one hand, it didn't add a lot to the game, but on the other, it didn't really bother me either, it was kind of nice that it gave you a way to choose when to level up, but there are other ways to do that as well, like just having a "level up" button in the menu that you can press if you're ready to gain a level in order to bring up the level up screen.
However, whether we are talking about a graphical representation of a perk tree with branching nodes and prerequisites based on the level of each skill or a FO-style list of perks requiring minimum skill levels or other perks as pre-requisites, ultimately the underlying mechanic is the same.
Indeed, changing the way the menu for perks is presented doesn't really change much, the main functional difference between Fallout 3's perks and Skyrim's are that Skyrim's perks are sort of like sub-skills, allowing you to further specialize in a skill, such as having a perk under one handed skill that gives you bonuses when fighting with a mace, whereas Fallout perks are general bonuses or abilities that may or may not be related to a specific skill, some perks may allow you to carry more, others might let you do more damage to a specific type of enemy, some perks may just increase a specific skill by a certain amount, so while the mechanics of choosing perks are similar, the differences lie in what they do, but it doesn't really matter. Fallout and the Elder Scrolls are different games, and just because something works well in one series doesn't mean the other needs it, but the inverse is also true, there's nothing wrong with including features from Fallout in Skyrim, provided said features could also work well in Skyrim, whether a feature should be in Skyrim or not should be determined by how well it would actually fit the game, not by what other games have it.