A question of opinion, what do you think is the most broken build in the game? Is it okay to have two builds because surely one will always be with abomination.
Abomination Mage Lona. Though in this 0.9+ version of the game, this build has been nerfed hard, not in the damage but in the animation where almost every spells she cast, especially thunder and water spells, makes her go into a long animation lock. Those spells used to be much snappier, faster and flexible, the water shoot spell in particular had 2 good variations whereas now it only has 1, a worse one that is the exact same as Deepone's. While I understand the reason behind the nerf I still heavily hate it as it makes playing the Mage clunky now, so I keep a copy of the game before the nerf (v0.8.9.2.2) where both the ennemies and Lona are more ferocious in their animation. Though, even then I still think Abomination Mage Lona is the strongest and most flexible build in this later version of the game, it can tackle almost every situation. In fact, there's one thing Mage build can do that other builds can't, and it's killing NPCs you shouldn't normally kill without decreasing morality using Malicious Spore's blood puddle, like here
It makes a lot of things like robbing the bank a lot easier
(If even this is going to be nerfed in the future then oh boy I'm going to consider v0.8.9.2.2 to be the final version. I'll probably play the later version after a major content has been added.)