Dievdirbys is not a phenomenal dueling class. Anyone with common sense will avoid your owls. Usually to win duels you must land Incineration in order to win.
In contrast, Dievdirbys can shine in the hectic 5v5 TBL environment, since people aren’t as cautious of solely you and your status. Bokor will win 1v1 since once Hexing lands, they need only press one button repeatedly to win without having to worry about catching. Though with more and more people getting Rheivsan gear it’s getting harder for Bokor and Warlock to deal their fatal damage in a short time window.
This build carries through team play. It’s capacity for winning situations where it’s you vs. many is less than that of Bokor or some of the other Cleric classes. But through it’s assets it wins by supplementing the team’s ability. In a way, it’s an offensive support.
When it comes to damage, which is what you appear to want to do, the best times are capitalizing on your teammates. Psychokino that use Raise, or a Freeze for example, make it very easy to land Incineration, a skill people seldom survive unless they have a Cleric on hand immediately. People talk about Incineration being useless simply because it’s difficult to land but the reality of TBL is that you can wait for moments like hard CC to land one of the most powerful DOTs.
This will be easier with R8, since Plague Vapors is fairly easy to land and even easier to hit multiple enemies with, through Pandemic.