When Aatrox is worth a pick, when it is worth a ban, and what its kit commits your team to.
Locking Aatrox commits your team to a fight pattern: trade repeatedly, survive the return damage, and win the third exchange rather than the first. A draft that cannot support that pattern does not improve because you play well.
At 175 attack range Aatrox has to walk into damage to deal it, so every trade begins with a decision about whether you can afford the walk.

Periodically, Aatrox's next basic attack deals bonus magic damage and heals him, based on the target's max health.
Aatrox slams his greatsword down, dealing physical damage. He can swing three times, each with a different area of effect.
Aatrox smashes the ground, dealing damage to the first enemy hit. Champions and large monsters have to leave the impact area quickly or they will be dragged to the center and take the damage again.
Passively, Aatrox heals when damaging enemy champions. On activation, he dashes in a direction.
Aatrox unleashes his demonic form, fearing nearby enemy minions and gaining attack damage, increased healing, and Move Speed. If he gets a takedown, this effect is extended.
Difficulty 4 of 3, melee, fighter. Those three facts decide how safe this is to pick first, and the melee ones are almost always the riskier blind.
Worth reading even when you are the one playing Aatrox: it is the list of what your opponent is being told to do to you.
Once honored defenders of Shurima against the Void, Aatrox and his brethren would eventually become an even greater threat to Runeterra, and were defeated only by cunning mortal sorcery. But after centuries of imprisonment, Aatrox was the first to find freedom once more, corrupting and transforming those foolish enough to try and wield the magical weapon that contained his essence. Now, with stolen flesh, he walks Runeterra in a brutal approximation of his previous form, seeking an apocalyptic and long overdue vengeance.
Full Aatrox page — abilities, stats and every skin →