I think that partial level scaling should be in place - for example every dragon starts out with lvl 50, so that a level 10 player will have no hope against them, and remains there until player reaches level 40, at that point at last half of the dragons should be kept at player lvl+10, so fighting them is always a challenge - you learn to fight dragons, but they, being intelligent, learn to fight you in turn.
I never have, and never will, understand the absolute camps.
Mass amounts of scaling ruins an RPG. Running into a common bandit wearing a full set of enchanted max type armor who can use highly-skilled attacks utterly shatters any sense of immersion in an RPG. So does running into a pitiful little level 2 Dragon or demon or what have you.
No scaling at all ruins an open-world game. Level-gated content puts up 'invisible walls' that restrict you from content. Having to trudge through a cave filled to the brim with level 1 diseased rats at level 30 just because you missed a quest is not fun- for most people. Neither is constantly getting destroyed by, again, a bunch of common bandits.
TES is not a shooter. TES is not a linear game.
Honestly though, the answer is painfully simple. And I could swear I've seen it implemented somewhere before.
All enemies scale within a set level range. For example, all Rats are leveled between 1 and 5, all bandits are level 2-7, all Liches are level 15-30, all dragons are level 40-60.
And they scale within those bounds appropriately, with some amount of randomness. So a Rat can't be higher than level 5, meaning they quickly present little threat. However, being rats, they never out-level
you. They scale at random to be no more than the players level, and no less than two levels below the player's level or their own cap. So at level 3 you can run into level 1 rats, level 2 rats, and level 3 rats, and at level 20 you will usually run into level 5 rats, though you can also run into level 3 and 4 rats. On the other hand dragons would maintain at least a, let's go with the quoted post and say 10 level advantage over the player, but they can't be lower than level 40. So at level 5 if you run afoul of a dragon, you're pretty much screwed, as it's level 40. While at level 45 they still pose a challenge as they will be about level 55- let's say +/- 2 levels.
The other bit would be making the higher leveled creatures rarer when the player is of a lower level, and giving the player warning if possible. So let's say that, for example, there's a cave on this mountain outside the town you're in. The townsfolk will talk about how it's a dragon lair, and how dangerous it would be for your meager level 6 warrior to go in there. Now, being level 6 there won't be a level 50 dragon swooping down to the middle of town to snipe you (which will happen in this town when you're level 40). But hey, if you choose to go check out the cave, you can. Or maybe you hit the cave before the town and no one has been able to warn you yet. Well, if you're lucky you might still be able to run out of there with your life. The other end would be that at, say, level 25, bandit's aren't going to be regularly trying to jump you on the roads. They'll still be in camps or outside ruins though. Also quests should generally scale to your level, with some amount of difficulty based on the 'level' of the quest- so becoming Champion of the Kill Things Guild should be much harder than say, becoming the Intern for the Bake Pies Guild.