so you got aatrox in aram, not the best pick but you decided to take a look in this guide to make the most of it. You will probably die a lot. if you do try to make the most of your deaths, so make sure your team is fed, so that when you initiate, you don't worry about dying because you completed your cc cycle and helped them annihilate most of the enemies.

cons:

Aatrox has a lot of drawbacks, you need good knowledge to play, and even then you can still be outplayed. his ultimate is perfect for 1v1, witch is unlikely to happen in an aram platform but the fact that it has fear helps on your survival and on your team to pick the right target as it clears the field a bit.

pros:

really freaking cool champion
very good ad scalings
his cc and utility is really good
he can outplay a lot of champions.