Soraka is quite a tricky champ to play effectively with (can be said for all champs) but her kit is rather very simple so it makes people think she is relatively easy to use. However, when i see people saying get Warmogs or hell Morello on her it does make me think these people still haven't grasped her kit yet. Now let me explain how her healing works very briefly.
At lvl 18 she has 1855 max BASE health
10% of that is 185.5 ~ 186hp
Her usual AP build is Ardent censor, Athene's unholy grail, Zhonya, (maybe rabadon) otherwise i get solari + boots + eye of oasis (for wards)
Without rabadon and usually with atleast 10AP from runes she has 180AP at full build
She would usually heal for 370hp at the end of the build (10% heals from ardent and 10% from mastery windspeaker)
While she sacrifices 186Hp + some mana for 370hp heals
Now try adding some more HP to her base HP and see what happens. Warmogs gives 800HP which means soraka now will have 2655HP
10% of that is 266HP she now has to sacrifice to heal 370HP of an ally
Point of the above calculations is ?? She needs to stack less HP as possible from items to decrease the flat HP loss she has from her 10% max health. Another drawback to increasing flat hp is that you will take longer to regenerate 10% max health if you had more hp (usually from her Q) thus she can heal less that way as well because 10% of tank soraka is alot more flat hp than 10% of base health soraka. With Athenes grail you can have a decent Health regen for every mana regen you get (which is alot in her kit).
Now lets look at Soraka healing Tanks -
They usually have 4k HP at max build. Soraka will sacrifice 186HP (10%) to heal 370HP (9%) of tanks Max Hp. You see the effectiveness of soraka is to get as much MR/Armor and heal the squishy carries of the team as much as possible instead of tanks. Not saying never to heal tanks :D
The health sacrifice is a huge burden on her but fortunately she has her Q from which she can sustain so well in lane but her heals are ridiculously weak early in lane. The reason soraka does so good is because she acts as extra health bars for the adc which means the adc is dishing out damage with the HP of a tank :D
Although her weakness is burst as she excels in slow healing but with her Ult + summoner heal + solari active + W can prevent atleast 1-2 outbursts on the adc. Which in team fights is more than enough.
Also athenes grail also stacks charges when you damage opponent and for 1 charge you heal 1 hp max 250 charges can be stacked which is alot and this has no CD. It's a must item on soraka but i usually always buy ardent censor first because it provides more burst healing and the passive gives ADC some lifesteal and AS. Soraka hardly ever has mana issues if you get ardent censor, eye of the oasis and Athenes unholy grail so the counter argument that she can abuse morello is stupid. Mana is not the issue here, it's her health sacrifice.
Lastly executioner calling an 800g item applies GW on targets which means soraka's heals will have reduced 40% effect. This probably means that at most cases your heals sacrifice same amount of HP that you heal your allies and i believe soraka already suffers alot from this 10% max health sacrifice. Her counter is to go burst against her and if people fail to realize this than those are probably the ones that will suggest she is broken and we need the item to counter her.
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in there somewhere to be even more of an 'ass'. :p
