My ideal system is such.
Only Level scaling in game effects dragons if its a MUST that allows both young and old characters to be able to take them down for the sake of the shouts and such also allows you to get away if need be for whatever reason.
Now everything is else has already pre-set level range at the beginning of the games. Also be aware levels do not entirely mean difficulty just what kinda spells/attacks/gear each are wearing.
Goblins level 2-5 their pests pretty much less organized then a normal bandit gang is at the bottom of the totem poll.
3-8 for Common Bandits If your level 3 or 4 the majority of the bandits will be 3-4 but there are a few in the upper levels which goes all the way up till you reach 8. Past level 8 at 10 or 12 the bandits will be locked at 8 thus removing the horrid I have Glass armor but I am still living in a cave eating mud crab meat. (Bandits locked at fur, rugged leather, and iron)
10-15 Bandit leaders (Goblin leaders included) are a step up they are more rare thus making them a higher level then a common bandit will allow them to seem more experience in what types of attacks/gear even spells they have. Ideally they will be wearing Steel or chain mail.
14-24 Mercenary groups are the most organized some groups may not be hostile at first but even the non hostile ones should follow the same. Common gear is Steel/chain-mail and now a bit of dwarven or enchanted armor pieces (not sets)
The Most difficult organized humanoids will be Cults or guilds either that be like the Theives guild, fighters guild, Dark Brotherhood, somthing like the Black water. Has a variation of level ranges since guilds are mostly hand crafted it would ideally range from 8-36.
New recruits are level 5-10
Experienced members being the same as mercs at 14-25.
Highest ranking members and Leader will be at 28-35
Now for wildlife.
Deer mud crabs, dogs, sheep and any non hostile animal for hunting purposes or similar level 1-4. A Deer is a deer if you shoot it just because ones a 10 point buck doesn't make it stronger. This also included any other wildlife they may add like rabbits or pigs or cows but ya.. Deer is a safe bet those are not
Wolves, bears, sabertooths, etc. lvl 3-8.
Pack leaders, mama bears, and lion kings lvl 8-14. leveling system won't work for armor due to the fact they have no armor it just what kind of attack effects it has a wolf has a simple gnaw or rip with claws attack pack leaders has attacks that could make you get a bleed effect or something similar
Creatures
Common monsters such as Trolls, Skeletons, Orge, Minotaur, Imps all fall into level 5-10
Undead follow level 10-35 (Lichs being most powerful Skels being the most common thus lowest)
Magical, or Dedric creatures(if appear) level ranges from lvl 15-40
Thats all I can think of atm, also should be handcrafted original rare creatures throughout the world that go from level 40-50 if your level 10 and going against it your going be wiped but if they implemented it so they only show after level 35 or something that wouldn't be much of an issue.
Again if your level 4 and your going against something like Bandit leaders it will still be possible only difference is they have better armor possibly better skills/magic so it will be tougher then a bandit but it will be possible.
This will never be implemented in Skryim though so I ask for a simple hardcoe mode or hardcoe damage mode to have