The basic premise of this "guide" is incorrect. Also if you can't handle surviving with only potions and health globes then simply don't play like you can?
You seem to misunderstand the point we're making. If you're using those runes and passives, you're not using more offensive ones. With enough mitigation and on-gear Healing, it's possible to not have to rely on skill/passive crutches as often for survival's sake.
(And honestly? I'd prefer using an escape/slow skill to avoid getting hurt/killed rather than be put in a position of having to take damage and get my life back, unless I can build a way into low-to-0-damage-taken builds, a niche Crusaders fill with ease.)
These discussions are without those things in mind. Both skills/passives that restore life as well as escape skills only further extend our survival. The root of it begins at our core, the equipment. That's what we're talking about.
Now, concerning those skills you linked that provide +% life per hit, that's quite fine and all but it's the same thing (meaning, regardless of how life and mitigation are skewed) so long as the eHP remains the same. With the same eHP but different weights on both Life Pool and Mitigation, they restore the same effective percentage of health per use.
200,000HP & 50% mitigation has 400,000eHP restore 240,000 base eHP per potion.
100,000HP & 75% mitigation has 400,000eHP restore 240,000 base eHP per potion.
Ah, but what you can
work with during combat concerning Healing and waiting for that potion matters more as eHP is skewed towards mitigation further and further.
If you get hit by 20,000 damage once a second, and have 5k LpH (coeffient = 1) attacking once a second:
With 50% mitigation, you take 10k damage per second and losing 5k HP per second..
With 75% mitigation, you take 5k damage per second and are breaking even.
In one scenario, you'll eventually be forced to use a potion. In another, you'll be able to sustain until another threat decides to bother you alongside your current one.
As an aside, I brought up Health globes and potions restore +X life
because this affix helps more with Toughness skewed towards mitigation rather than life pool, just like LpS & LpH. Put simply: The smaller your HP pool, the easier it is for both restoratives to fill you up using this affix.
Let's say you have +20k Healing Globe Bonus:
If you have 200,000HP, a potion will heal you for (.6 * 200,000) + 20k = 120,000 + 20k = 140k, healing you for (140,000 / 200,000 * 100%) = 70% health.
If you have 100,000HP, a potion will heal you for (.6 * 100,000) + 20k = 60,000 + 20k = 80k, healing you for (80,000 / 100,000 * 100%) = 80% health!
(Of course, once you've used one, you're back to waiting 30 seconds hoping to survive long enough... nevermind that this is moot if you're forced to pop it early due to reflex...)
(Edit: General hootenanny, and Battle.net bothering me with login during the post made me post before I was ready.)