Dead is Dead can be super fun in Oblivion, Fallout 3, New Vegas and Morrowind. (though it can get stale in FO3 and Morrowind after certain points, can't recall if Oblivion's got stale)
In Skyrim though, the problem is this....here, in case you don't want to read, I ATTEMPTED to highlight it with https://www.youtube.com/watch?v=ddtqyVeolb0 (please don't freak out at the sarcastic and hyperbolized title)
In a nutshell if you'd prefer to read: Because Skyrim's killcams merely compare his damage to your remaining HP, they activate instantly the moment the enemy ATTEMPTS an attack. He doesn't have to hit, he just has to attempt. The result is that if an enemy can twoshot you? He can oneshot you. Why? Because after the first hit kills 50% of your HP, the second can potentially trigger a killcam and lock you in place IMMEDIATELY.
The solution? You stack health and defense. You stack it to the point that no enemy can possibly two-shot you, and you of course aim towards the strongest enemies in the game. So if the strongest enemy in the game can hit for 500 damage? You get 1001 health, or stack your defenses high enough that his 500 damage drops to below half of your HP. The problem is that if you build your character towards the strongest enemy type, you're ridiculously godlike compared to everything else. This couple with instant heal potions and being able to pause combat to heal at any given moment means that of COURSE you pause to heal if you happen to take a single hit, knowing damned well that NOT doing so will mean your death. The result is an incredibly boring experience. If you happened to bother watching the vid (honestly not that entertaining), I actually ATTEMPTED to find the most deadly areas in the game I could think of, so the "excitement" shown there is the best it gets.
The same issues with 80% Damage reduction has existed in past titles, but it's been less severe because for example Oblivion had stagger that could keep you out of your menu to heal (as well as a 5 potion heal limit, though that had a loophole workaround you could exploit), FO3 did have a slight delay to open your Pipboy unless you hotkeyed stimpacks and Morrowind? Morrowind simply had a good variety of enemies with no real mercy in that regard, so even if you became godlike there were still enemies that could oppose you. New Vegas circumvented the issue entirely by changing the defense system.