I started a new character last week, an immortal/larger-than-life hero concept which uses a custom race (based on Nord), and the following traits & mods:

• 100% fire/ice/disease, 50% shock/poison/magic resistance
  
• Nighteye at will
  
• 200 "unarmoured" armour rating (when no light/heavy cuirass is equipped)
  
• (Effectively) unlimited Stamina, slightly faster Health regen
  
• A few custom perk progressions
  
• No spells or Magicka use at all
  
• No useful alchemy/enchanting use, no smithing use at all
  
• No healing or other potions used (poisons only)
  
• All skills start at 1, training allowed per level = 1

Currently using some basic mismatched armour types, alternating between shield & sword, bow, and a basic Draugr longsword modded into a two-hander. My character is level 9 at the moment...

... And she's started running into a lot of higher-leveled monsters. Met a Wispmother that nearly killed her not far from Helgen, a Giant Frostbite Spider that did kill her (thankfully I'm not playing with just one life, due to time constraints), some stronger Draugr, and a small army of mid-level bandits - although the bandits are only notable for their significant amounts of Health, and she elsewise goes through them like butter.

I'm enjoying the playthrough, but the enemy encounter scaling seems off for a sub-10th level PC - have I just been (un)lucky recently, or does the game take stats other than level into account for the purposes of scaling? Anyone else tried an enhanced character playthrough and noticed any similar or odd behaviour with encounter spawns?

No guarantees for modded characters.

I've bumped into that Wispmother, with a normal level 1 character, and come across a spider with a normal level 4 that took 5 reloads to kill. The scaling is only partial, so seems you just went too far off the beaten path.

I've met a Wispmother before I even made it to Whiterun, so I guess I was below lvl 5,