Yes you heard right, that's a mod idea of mine. Basically, making perk trees, that act as lesser, extra versions of choosing 10 extra magicka, stamina, or health each level. With hundreds of ranks in each of them. Unfortunately though, when I look at entry point, in a perk, I do not see, modify health, modify magicka or modify stamina. So I'm not sure if my idea is EVEN possible, as worst case situation it might go against hardcoded game mechanics.

For example, per each perk point, you can have 1 (or maybe 2 if that's too weak) extra health magicka or stamina. I KNOW that sounds infinitely weaker, than actually, eventually mastering everything, but the mod would increase roleplaying potential by getting rid of excess perk points at very high levels, allowing you to at a snails pace use the perks to become gradually stronger, but without turning you into a master of everything, and with the perks having been spent the temptation to do that, being much less of an issue, and at least you'd have SOMETHING to spend them on.

Before you say, "But won't that make the game a lot harder?", "wouldn't that be NERFING my character for almost nothing in return"?, the point being that this type of mod would encourage you to specialize your character.

The idea being, to increase roleplay potential for people who don't want to eventually be sneaky as chameleon, strong as a mammoth, agile as a cat, hard to kill as every boss from every TES game combined, magical as all of house Telvanni, a master archer, a master at two handed, a master at one handed, a master in every magical school to the maximum level /etc/. In a sense, yes, intended to make Skyrim more difficulty in a way. And also to help you be able to customize your stats more, having a larger potential health or magical or stamina pool, but since perks increase these things so incredibly slowly, it would be balanced.

And before anyone says "Well then JUST don't SPEND your perk points", having all these built up perk points at very high levels, I spend on nothing, and at ANY TIME being able to become a master of everything with those extra perk points, is INDEED immersion breaking to me. Sometimes adding immersion to the game, is about the option of being able to commit to something, even if it shuts you off from other options later, such as this perk idea.

As I personally, like making things with inbuilt challenges like melee characters who can't sneak effectively or use powerful ranged attacks, mages who can't melee effectively, and stealth type characters who have to use deception, manipulation, and comrade assistance to survive. Which is why I've been today, considering making a mod that does just that. Instead of being a master at everything, you can have a slightly higher attribute pool than you would normally have had.

It would also synergize incredibly well with mods that add extra perk points for overcoming some challenging trial, now you can indefinitely use those perks to specialize in a specific role, and these three attributes alone, aren't enough to make you a master of everything anyhow.

Sure, it's possible to make perks affect health/stamina/magicka. You would use Perk Entry Point, choose the "Ability" radio button, and then add an ability that increases the value by whatever amount you want.

However I think the real problem you're going to have with this idea is rather the fact that new perk trees can't be easily added to the game. You would have to develop your own entirely new perk tree menu using Flash and ActionScript, or else you would have to resort to a clunkier MCM fake-up of a perk tree, or something like that.