How about a new rune? Inspiration path
We all have seen how this rune: https://i.gyazo.com/8f72b23249e6c7d2463b05c0d8cf6f52.png
Has opened up new build paths and I don't just mean the yolo

but several meaningful full builds with 40% or 50% cdr in them.
Yet still to this day I as an Akali main have to look at items like:
and think to myself "now if only this item had a bit of HP instead of that mana on it".
This is not about just Akali either. There are a ton of champs with energy or no resource that are practically locked out of any items with mana on them simply because every point of mana on those items is 1.4 gold they are throwing away.
https://i.gyazo.com/918e8d72abe55b4195bd44b498a177ca.png
The items become less slot efficient and even if they have wonderful passives or actives you simply have no access to them because if you buy the item you get behind in raw stats.
Another thing that puts you off items as a manaless champion is when they have mana regeneration.
We know that 1 HP = 2.6 gold and 1 Mana = 1.4 gold.
Now imagine what if there was a rune like this:
https://i.gyazo.com/6eb0299f26718c041485962494283eaa.png #Hextech Mana Reinforced Armor (placeholder name and icon)
I would prefer exoskeleton for the name tbh (but that may go on biowares turf)
Flavor text: The latest hextech armor has the ability to absorb and crystallize the mana of it's owner and reinforce him with supernatural defensive power and regeneration capabilities. Actual stats: Converts 60% of bonus mana into half the HP and 50% of your bonus Mana regeneration into HP regeneration.
##How it works:
You probably noticed the word "Converts" so let me make a clear example:
If you are a mana champion and you buy
you will get 40% of 400 mana =160 and the other 240 mana will be converted into 120 HP.
So 160 Mana and 120 HP.
A champion with no mana will simply get 120 HP.
If a mana champ buys:
Instead of getting 150% Mana regen they will get 75% mana regen and 75% Hp regen ( item already has 50% HP reg so 125% HP regen total)
The champion with no mana just gets 75% HP regen.
So if was playing Akali I could buy
and get 30% of that 250 mana = 83 as HP.
Bam 216 gold from the rune.
Now the item is not 71% gold efficient on me in term of stats.
It gives me 77% gold efficiency and currently mana champs get 81% out of the item.
I could also get a Morello and it won't be a loss of 560 gold for mana. I will get 312 of that gold back. Item is still giving me less stats for my money than a mana champ but it's not a shocking robbery. I finally get to have healing reduction without opting into a thormail...
#Disclaimer - numbers can be tweeked a bit to serve the balance but I want your unbiased opinions in the pool.