TL;DR: Each level in the runes system needs more options with greater risk/reward structure so you can customize your character to the way you want to play it, instead of just stacking damage and saying to hell with it because there's barely any choices to resist the obnoxious output of damage.
In addition to the Resolve tree granting you health, I feel as though if it's your primary role, it should give you a small boost into armor and magic resist, perhaps +5/+5, furthering the concept of "Live forever, AND durability".
If you want constructive criticism Riot here it is:
You gutted runes (great!) and attempted to scale everyone's armor back up. The problem lies in the %'s and what's offered. You gave AD dealers AD to get back up to their "regular" state after gutting runes. Then, most AD dealers take trees which give them either more power, effects, or flat out AD/AP (adaptive) on TOP of the buffs to "restore them" to a regular state.
On the flip side, there's little to no options to REDUCE or mitigate damage, and no, +5 armor/MR is not the "Go to" finger pointer. Do you realize, % wise, how much damage +5 armor even would even reduce? Stack that with +5% armor at the beginning of the game for being FORCED to pop a potion or have some sort of innate sustain to get the effect. I could mitigate damage more with the runes offered in the previous system that I ever could here.
In fact, take any tank champ into the game and play it out. In last season we had an option for +5% armor/MR in Masteries RIGHT FROM THE START OF THE GAME, and in addition we could choose to stack more armor, scale our health, get some CDR, it felt like I had OPTIONS.
One of the most viable aspects of this system that I feel is overlooked is the fact that I don't feel like I'm making choices. If you're NOT a ADC/Assassin, I feel like you're forced down certain paths simply because even with the megar bonuses offered, you are forced to take those paths because without them, you're not viable at ALL.
AP, Junglers, and non-damage supports are left in the void as well as many other champions.
Especially as a tank, I don't feel like I'm making decisions or have that many options available to me.
For example, a better option in the resolve tree would have been something like this:
Gain 15 armor, but deal 10% less damage for 10 minutes.
OR
Gain 15 Magic resist, but deal 10% less damage for 10 minutes.
OR
After 10 minutes gain 8 armor AND magic resist + 5% armor and magic resist.
OR
Gain 20 armor AND magic resist, but deal 15% less damage to champions and monsters for the first 15 minutes of the game.
OR
After 5 minutes, for each minute passed, gain 1 armor and 1 magic resist.
This gives me more options and actually makes me FEEL like I'm making a choice with clear consequences or benefits so I could choose to walk in more tanky or wait and get clear benefits and losses for each choice, depending on how long I think the game is going to go.
It also makes it more viable to go into certain match-ups or survive longer. These are arbitrary examples, but you can see my point. The whole system is missing things like this. Instead there's 3 options at each level, multiple of which are not even VIABLE for the "class" or champ you're playing, so you basically go into 1 rune selection, maybe 2, just because you ARE the class you are, and the runes only work for you.
In conclusion, there needs to be more choices, more keystones so there's more options for a lot of different classes. Right now I feel like there's the typical 1-2 paths that can be played for most champs, if at all.
With more keystones and choices, you'd encompass a large variety of champions and offer a lot of mix-match benefits that could expand the game more and offer a metric ton of different ways to play champions because you have more options available to you.
