Balance patch 9.3 just hit the live servers, and it toned down a number of oppressive champions by making them more susceptible to counterplay in-game. Five champion changes that were highlighted by Riot on the patch notes were for Aatrox, Akali, Irelia, Cassiopeia, and Camille.
From the 9.3 nerf-list, Aatrox may have been hit the hardest. Although he received a small buff to his Health Regen and Health Regen Growth, it's hardly enough to compensate for the immense nerf to his 'E-Umbral Dash'. The healing property from his E skill's passive was changed so that he can no longer heal from minions and monsters. Not to mention, he will no longer be able to store a second dash charge, and its cooldown has been significantly increased.
Aatrox players will now have to be more careful with how they utilize their E - whether to use it offensively with their Q combos or save it as an escape tool when things go south. The passive change, on the other hand, will largely affect the viability of Jungle Aatrox and how the champion is played in the mid-to-late game where split pushing becomes prominent.
The second champion that was hit by the nerf bat was Akali. Before the patch, 'W-Twilight Shroud' gave Akali almost perfect safety when turret diving, making her immensely oppressive when she has the lane advantage over her opponent. Now, she will no longer be able to stay hidden inside her shroud when under an enemy tower, and its late game cooldown has been slightly increased. Although this change alone will heavily shift how Akali will be played, her 'Q-Five Point Strike' was also hit by the nerf-bat.
In exchange for an increase to her Health Regen from 3.5 to 6, Akali's healing from her Q skill was completely removed from the game. With this change, Akali's lane sustain will drastically decrease; and will cause her to be much more careful when trading in lane. Akali will no longer be a safe champion to blind pick - especially in the top lane where sustain is vital - and will be a situational pick at best.
The next champion to be largely changed is Irelia. Irelia received a bump to her base stats in Health Growth and Armor. Her passive was also changed so that her 'Ionian Fervor' no longer grants per stack on-hit damage when not fully stacked - but she will now gain an attack speed bonus for each stack she accumulates. Her 'W-Defiant Dance' was also changed so that it gives 10% more damage reduction to physical damage, but has had its 40% damage reduction to magic damage removed.
With this change, Irelia's instantaneous burst damage has been decreased, making her less oppressive in the mid lane when up against squishy mages - especially since her W will also no longer reduce incoming magic damage. With these changes, Irelia is now more fit for the top lane than the mid lane, and she will be more susceptible to being counter-picked.
Camille is a fast-paced and fun-to-play champion that has been a part of the meta for a long time. She is a pick that can flex as both a jungler and top laner, and Riot wanted to set a definite direction for her moving forward. Having been a jungler with strong gank potential, Riot couldn't find a sure-fire way to tone down her jungler capabilities without making her top lane 'suffer'.
Riot changed Camille so that she can no longer stun minions and monsters with her 'E-Hookshot'. Although it may seem like a small change on the surface, this change will significantly decrease Camille's sustain in the jungle. The blade-legged lady will now have to pay more attention to her health while jungling and in turn, will have to be more careful with how she counter-jungles.
The last champion nerf that was highlighted by Riot on the patch notes was Cassiopeia, and the change she received is the smallest of the five on this list. Her 'Q-Noxious Blast' received a decrease to its base damage but had an increase to its AP ratio from 0.8 to 0.9. Cassiopeia's 'W-Miasma' was also hit with a nerf that affects its late game damage and mana consumption.
The 'base damage for ratio' on her Q is actually quite a fair trade; her DPS won't see any significant changes. The same can be said for Cassiopeia's W, as its main purpose was to CC and zone, not DPS. The damage and mana cost of 'W-Miasma' is exactly the same as before at level 1. As most players maxed 'W' last anyway, it'll barely affect how Cassiopeia is played.
In conclusion, Aatrox and Akali will become very niche picks that are insanely difficult to play as efficiently as before. As for Irelia and Camille, the two will become more top lane oriented. And lastly, for Cassiopeia, she will remain essentially unchanged.
*Images by Riot Games