Why was Soraka reworked?

Before she was a low risk meh reward battery and Riot found that boring so they made her a high risk high reward ambulance.

Does anyone know why she had to be reworked?

Generally speaking, reworks happen because Riot realized they made a champion with an awkward mechanic/playstyle that was unfun/lacked counter-play/takes away from the game. All in a way where tweaking the numbers on the kit itself can't push them away from those problems.

Soraka's main issue was she just created a snooze-fest lane with no interaction, rendering poke and any trade that can't OHKO someone essentially obsolete and a waste of time, while also granting that swag mega-armor bonus on someone in the middle of an OHKO attempt that also heavily punished doing things outside of snooze-fest farmvill strategies.

Which was subsequently a huge problem if Riot allowed her the numbers to be viable, as making your ADC invulnerable in lane with a very low-risk stratagy is, well, really low risk. And low risk > high risk when it comes to winning stratagies, but high risk is more enjoyable and fun to watch.

Back in the day, she was a nightmare for every person she laned against.

I played pantheon top, who is a lane bully, yes? Soraka would just silence me if I tried going in, and healing back all of the damage as I hit her and proceeds to spam Q to take most of my health. You couldn't farm near minions, you would get silenced (which was free, by the way) and then hit by multiple Qs, or if you tried to go aggressive the same result.

It was an absolute frustration to play against, and people kept calling me "bad" when I could do absolutely nothing to the goat. She was actually called satan for a short time by some people pre-rework when this obnoxious playstyle was found out.

In addition to what others posted, they've always wanted to make a core healer character work (notably soraka), but mobas are not the best game to support those archetypes as being op at healing means you will just win almost every time and being up means your heals generally never matter in the scheme of things.

The way they did her rework, they made it so that Soraka can be THE Heal support of League without being ridiculous to play against. The way they did it was pretty great: Costing a percent of her health to heal allies for a pretty nice amount, which goes hand in hand with being a healer: sacrificing oneself to save others. It allowed for amazing heals without making her lane unstoppable as she is just shifting damage from others to herself. It also made it so she wasn't a kill champion (because her old kit actually had some pretty decent killing potential by herself.)

Basically added more risk/reward to her: The enemies can go destroy her face since she doesn't have amazing self sustain so they stop the other team from being so sturdy, but she pulls it off right, she has THE highest healing potential in a fight of any support in the game and makes her team take plenty of punishment.

Because solo lane soraka was literally the most unfun to every exist