Getting enemies stuck on terrain is not exactly an achievement of the player, it's a failure of the game. Killing enemies with summons that they almost automatically attack instead of you isn't hard either. Hit and run against enemies that won't chase you beyond a certain distance is also pretty simple. Using abilities that completely incapacitate enemies for long periods of time, which they cannot counter in any way...well that's obvious. And so on and so on. Certainly, these are things that could technically be considered tactics, but they're not rewarding or challenging, you're simply taking advantage of bad AI and you know it. The nature of the kind of AI used in video games means it can always be taken advantage of, the difference though is that good AI makes it fun and is more effective at masking it's limitations while bad is, well, like Skyrim - obvious, predictable, easy to exploit.
"Absurd health" might be a simplification but that's how it actually feels like in practice, regardless of the mathematics behind it. It's absurd health relative to damage you deal. It takes more than 2x the number of strikes it does on normal to kill a master difficulty enemy.
That's funny, because you didn't really mention anything in particular that I had in mind. I was thinking more along the lines of timing, movement, learning enemy attack patterns, being aware of your surroundings to further supplement your footwork as to not run into something and get stuck, consistent execution, versatility, etc. You're not exploiting the AI if you're doing something besides participating in a stand-still turn based style of combat, you're just playing the game.
Seriously, nearly every Youtube video I've seen of Skyrim combat consisted of players just standing in front of their enemies without utilizing any movement what so ever and then spamming their attack key while getting hit countless times unnecessarily. Forget using footwork. Forget using block. Forget using distance. Forget learning enemy attack ranges and your own attack range. Forget playing the game, just mash your buttons with your super awesome gears yo!
PS. In practice it doesn't feel like absurd health at all, that is unless if you don't have something to compare it to. If you only ever play Master and are lacking in some areas you might think, Oh hey, I bet Adept is much easier than this! It's not. Compared to Oblivion where you would do 8 TIMES less damage and receive 8 TIMES more damage, Skyrim's Master difficulty setting is nothing. Now that was a severe case of absurd health. Skyrim is no where in the same ball park.