I disagree with the Soraka changes, because I feel like it is shifting power away from Soraka's core fantasy and spending her power budget on stuff that distracts from her identity.
Right now, starcall's primary purpose is to drain health from enemies so you can use it to heal your allies. Under the new system, starcall's ability to self-heal is brutally nerfed, and in exchange, you are given incentive to rank starcall (making it deal more damage) and spam it (due to the mana regen it offers) The problem is, if you don't get HP from starcall, you can't heal others, because astral infusion costs 10% of Soraka's max HP to use. And if you don't heal others, you aren't fulfilling Soraka's gameplay fantasy.
These changes hurt your ability to drain health (and thus your identity as a healer) as follows:
1: Currently, you rank W to increase healing on your Q. With this change, you must rank Q to increase healing on your Q, and W to rank your ability to heal your ally. This leads to multiple-ability-dependency, nerfs healing by a level or two on either starcall or infusion (your choice) until about level 13, and drains power from equinox (given that it must now be maxed last instead of ranking starcall last.)
2: Restoring HP on Soraka is *greatly* more valuable than putting on an ADC. (Example: At level 5, with three ranks in infusion, Soraka can burn 77 of her HP in order to heal the ADC for 130+60% AP. Even with no AP, that means every HP on Soraka converts to 1.7 HP on an ADC. That's down from 2.3 HP on live, by the way...) Because of this, you would *never* want to transfer your alignment for in-lane sustain healing unless your ADC needs mana.
3: Related to above, you can indeed transfer mana to your ally, but look at the numbers. At level 5, (three ranks) it gives 40 (+10% AP) mana to your ADC.That's about 4/7ths of a piltover peacemaker. 4/5ths of an ashe volley. 4/5ths of an ardent blaze. The opprotunity cost is too high. It's *way* better to heal yourself so you have more HP to spend healing your ally. This, along with 2, above, makes almost any use of alignment transfer a trap.
4: Due to points 2 - 3 above making alignment transfer a trap, you must wait 5 seconds to heal your ADC after any successful starcall to gain maximum healing effectiveness from your starcall. This lack of flexibility greatly impacts her role as burst healer!
5: Soraka's ability to self-heal in late-game teamfights is greatly diminished. Right now, in a late game teamfight, you can peg 2-3 enemy champions piling on your front line and basically be full health. Now, you get back... 90+10% AP hp and 60 mana? Over 5 seconds? This is entirely non-useful at level 16-18. That's not even enough HP restored to fuel a single heal (which costs 165 HP at level 16).
6: To add insult to injury, astral infusion's base numbers have been nerfed!
In exchange, we get a few benefits. First, starcall is now easily spammable, because the mana cost has been lowered. Starcall is likely to deal more damage, because we are forced to rank Q. Starcall has more reliable CC. The problem is, none of these changes fulfill Soraka's core fantasy; that of being League's foremost healer. When I play Soraka, I don't _want_ to carpet bomb enemies with endless starcalls like the pre-rework Soraka. I want to heal people. I recognize there is some benefit to this, but they are not the benefits I want.
I would love it if a rioter would provide some context here. I'm only a lowly silver, so perhaps I'm missing something, but this seems like the most brutal Soraka nerf I have ever seen, unlike the last Soraka update, where they just swapped power around to fulfill Soraka's core fantasy at the cost of a bunch of other abilities that didn't make sense on her to begin with.