I don't think starting with a blank item is better though.
   I think this way is better because the devs can still control balance.
   I think it's ideal to have the tree exactly like that for each item. 2 choices for the first upgrade(upgrade 1, or upgrade 2), 2 choices for the 2nd upgrade(the other upgrade, or lvl 2 of the current upgrade.)  And then the last upgrade is forced based on the first 2 upgrades.

  Like one item should have a +damage aura, yeah, as one of the 3 paths.  But you might have to choose upgrades before it that you don't like.  (Like in my example say I want that middle example that gives all "%chance skills/abilities a 10% increased chance to trigger".  I might want to have higher IAS instead of some IAS, some amor, but I sacrifice some IAS to get that bonus instead of the double-hitting chance.)

  I thought about single level upgrades(have items like the current ones, have like a lvl 2 and lvl3 upgrade that boosts its stats across the board, maybe adds a new stat at hte very end.)  And I thought of being able to simply add whatever you want..
  But I think this way would be best for the variaty, gameplay, and flow of the game.

  If you could just put any upgrade to any item, people would be more likely to always pick the same ones.  The tree requires you to make choices

Actually, what i mean is just like putting 5 base items into a starting point of the tree, it'll be easier to consider all the possibility of upgrading in a single page. Better than clicking at shop to see base items and then click on upgrade shop to see how we can upgrade them.

What i mean is there's still a tree for stats boost as you suggested, just passive and active to be added. And not you can add any, there's a set of skills to added into boot for example: you can add only +10% movement aura, +10% armor aura on boot. We can make balance by changing cost to add the skills and removing skills from this set.

This way the combination is so vast and you can make it suitable for countering your enemy play style during the match. Say if you are forced to get ability depend on the upgrade stat tree, sometime you may end up getting some stats that don't really needed and that's not the best for the situation you're on for sure. Also i consider this to be a way you can get active skills earlier in the game by just getting active skill first, stats boost later. but yeah the cost should be reasonably high to balance thing out between choosing stat boost and active, passive skills bonus.

Ah, please let the Artifacts be something special. At least they're artifacts!

Let them be good but expensive. They shall have the potential to turn the tables, support your domination or just give some cool additional gimmick. Like the -right now overpowered- Teleporting-Wand (posted something to this item in another thread).

Upgrading them wouldnt fit them, imho.

Also stacking is one thing. The most things should be able to stack like: Dmg, attack speed, move speed, crit chance, crit damage, mana/hp (+regen)

But also stuff that shouldnt stack like: reducing cooldowns (only Abrahams right now, but shouldnt stack its just to strong), dodge, chance on hit to activate something (exp. Lightning strike), also the % of lifesteal shouldnt stack.

An Aura + Item ok, but i dont like to see Rnd-DPS hero with 6x the lifesteal ring or stupid things like that. Maybe to keep it "real", you only can have 1 breastplate, 1 helmet, 1 boots, 1 gloves, 2 rings if you want and the additional cons + artifacts.

So long,

Aspartem

Oh yeah they'll be more expensive, but I'm saying still have an upgrade path..  It would give more options for activatable abilities.

But i guess not having them upgradable is fine too.

And Abrahams isnt' the only thing that stats.  There is an rob too with -25%.  If you get both it's -50%.
I think EVERYTHING should stack because then you have a question of "does this stack or not?"  It's easier to answere "everything stacks" not a list of what does and doesn't
It's more than abrahams should be 15%, and the orb 20%, so you can only get 35% with both or something.  And life steal needs to not be overpowered like in DotA (I dont think it currently is, just saying.)

And you wouldn't be able to get 6x lifesteal ring because you can only have 1 of each item.  There might be two, MAYBE 3, lifesteel items across the board.

For the record i think using 2 boots is fine..  or 2 breastplates.  I don't think gameplay should be hindered because "lol wut i can put 2 armurs on mah ruk?"

And Zeneroth, I think it's important to have the tree how i described it.  There is the whole "do I want to buff this one (set of) stat(s) on this one item, because those are the stats i want the most?  But I don't want the "bonus stat" at the end of that line as much, so should i choose to go for stats upgrading i dont want as much in order to get the "bonus stat" i want?".  You can only use one of the same item, so you can't get 2 of them to get the stat upgrades you want and bonus stat you want all the time.  It makes you make more decisions, and it will help with balancing out the items with balancing out stat upgrades vs. the bonus stats.
You only have 3 upgrades to choose from on every item.
I think that's a very good dynamic.

If you think you should only wear 1 helm, 1 breastplate, 1 boots, 1 gloves, then instead of selling those items in the shop, the shop should sell "crystals" that have all the stats, and you put that crystal in ANY item you want.  So you have "of Strenthening" which gives 15% ias and  150 armor, and you can boot that in boots to make "boots of strenthening" or a helm to make "helm of strengtehning" in which case you have 15% ias and 150 armor helm.

That way you can still get all the items you want..

Then they should remove the -% Cooldown , or reduce it to one item, and make all items "unique" so you cant wear two times the same item. Or something like that. If everything stack, you cant do something powerful unless for a huge ridicoulus price so you can only afford one in a normal lasting game.

I just dont like, it doesnt feel well for me. I can live with 2 Helms or 2 Plates etc. but no Itemstacking. With your idea itemstocking would be reduced anyway, because you have to upgrade it first etc. etc.

Nontheless.. Thumbs up for your idea

Stats like cooldowns, run speed and attack speed don't need to stack linearly.  I could be more like 1/(1+%) that way an increase of 100% would only cut cooldowns in half and 200% to 1/3.  It would create diminishing returns on that stat and prevent you from getting it to near 0.

Yes, i know that little about maths

And..doh.. i forgot about the "no double items"-Rule. Well.. then i'd could be ok, still 2 reducing items are to strong.

5.6 Cd for a 5 Cd stun is OP, i think we dont have to discuss about that. But that would be another topic about how pewpew Rook is

Stacking is ok, just make the items with strong abilities unique, so only one exist => no stacking of good items.. tata!

So long, Aspartem

I approve of this idea.

This plan is win.  I think the system is very easy to understand, and at the same time allows for a huge amount of gameplay diversity.

I'm not sure what to think about having two boots on at the same time.  I guess, as long as they are different boots and not the exact same thing, it shouldn't be a big problem.  They already plan to turn the "shopping mall" by your stronghold into one building, and after this the differences between boots and rings will become less noticable.

This plan also goes toward having the same Demigod play different ways.  Using items, you could either have a Rook tank people while dealing tons of damage per hit, or turn him into an unusually fast walking castle that charges people and hammer-slams them.  You could have a hit-and-run Regulus that moves quickly and has a high HP regen, or you could build him up to hold ground with a rapid fire crossbow and a cooldown reduction for Angelic Fury.  This hypothetical diversity is gained entirely from items, while using just the skills we have right now.

I'll have to agree with inno's last post that you should be able to select your 5 items through any combination of the shops.  Anyways with the stacking thing it would be best if 25% aspd + 25% aspd = 50% aspd.  The math would be easier and simpler to understand.  Just balance items so they can stack that way. -25% cooldown on two items is too much so simply lower them both by 10% or something.

I believe +25% and =25% attack speed is 43.75% more attack speed, but i'm not 100% sure.

I think that's the right way to stack though, personally.  The numbers one at a time.

the math would have to be basespeed *(item1+item2+item3)

er actually 2 25% IAS items is 56.25% increase I think

the +40% and +50% items are +110% attack speed, not +90%.

For balancing reasons.. yes.  Plus it's simpler this way for the user.

And you'd get rid of having to sometimes choose between a path you don't really want in order to get the "bonus stat" at the end of the line.