User blog comment:TB93/Ramiel ruling Hell/@comment-5619706-20170227185434/@comment-5619706-20170227191723

Abaddon was strong. I think you're confusing plot-direction into intrinsic character strengths. Abaddon in her first appearance had access to high-level spell casting, immunity to standard exorcism, terrakinesis, memory reading, exorcising lesser demons simply by touch, etc. Each of her subsequent appearance makes her drastically weaker because any players left in the board at the time are unable to realistically stand up to Abaddon--especially Crowley, who was half-way being cured back into humanity. Abaddon in As Time Goes By showed more strategic thinking and a great number of abilities compared to King of the Damned, where she just stood still and basically waited for Dean to kill her.

TL;DR, they dumbed Abaddon's character just so she could be disposed off