I really don't know why they would do that, she is a balanced champion, if she starts to snowball it's a beast, but can be easily countered with CC and she is extremely squishy, so what are the changes we going to have?
Katarina’s New Abilities:
Voracity (Passive): Champion kills or assists reduce Death Lotus' cooldown and refresh your basic abilities.
Bouncing Blades: Katarina throws a dagger that bounces from enemy to enemy, dealing magic damage and marking them. Striking a marked target with an ability or basic attack will consume the mark to deal additional magic damage.
Sinister Steel: Katarina whirls her daggers around her, dealing magic damage to all enemies in the area. If she hits an enemy champion, Katarina gains Movement Speed for a short duration.
Shunpo: Katarina instantly moves to her target's location and takes reduced damage from enemies for a short duration. If the target is an enemy, she deals damage.
Death Lotus (Ultimate): Katarina becomes a flurry of blades, throwing daggers with unrivaled speed at up to three nearby champions. Daggers deal magic damage and reduce incoming healing on targets hit.
Katarina’s Old Abilities:
Voracity(Passive): After a kill or an assist, Katarina gains 25 gold and her cooldowns are reduced by 15 seconds.
Bouncing Blade : Katarina throws a dagger that will bounce from enemy to enemy, dealing magic damage. Each subsequent hit deals 10% less damage. The blade won't bounce to hit the same enemy more than once on the same cast.
Killer Instincts(Passive): Each of Katarina's autoattacks and abilities will deal extra damage per hit. This gives extra damage to each Bouncing Blade bounce and each Death Lotus dagger.
(Active): Katarina's next basic ability within 15 seconds will have a bonus effect:
Bouncing Blade: Deals full damage to every target it hits and applies 50% healing reduction for 5 seconds.
Shunpo: Katarina takes reduced damage from enemy attacks for 3 seconds.
Shunpo: Katarina moves to her target's location, appearing behind it. If the target is an enemy, she deals magic damage to the target.
Death Lotus : Katarina channels for 3 seconds, throwing 30 daggers over the duration to the 3 closest enemy champions in a nearby area around her. Each enemy champion can be hit by a maximum of 10 daggers.
So what are the changes?
She doesn't win the extra 25 gold whenever she kills or assists.
When she kills or have an assist she will have the Death lotus cooldown reduced and abilities refreshed instead of reducing all cooldowns by 15 seconds.
Don't know if this will be positive for her or not... But I think it will , since she will now have all her abilities refreshed after assist or kill, so it will be easy to get another kill or assist.
Now we have a Q similar to Akali's Q , whenever an enemy is hit by Bouncing blades it gets marked, and when you attack them it will deal extra damage. In my opinion is even better than Akali's Q , since in a teamfight Katarina can mark all the adversary team , it's multi target and Akali is single target. Just due to this change Katarina will become really powerful.
In W I believe that Katarina lost a bit.. She now has an area damage that gives damage and movement speed for a short duration, the only good thing it will be for chasing enemies, while with the old ability she could hit every target with bouncing blades for the same damage and healing reduction( a great debuff) or have reduced damage from enemy attacks.
So the new Shunpo has the combo with W from before, everytime you use it you take reduced damage for 3 seconds. So it is a trade in having this here and changing W.
The only difference in her ultimate is that she now gives reduced incoming healing , what will be great against an ad carry with Heal as a summoner spell .
With this changes I believe that Katarina will be even stronger and will be picked much more. She will have more burst damage, so it will be like an Akali but more AOE oriented. What do you think ?