IMO DoT's are fine in game in general. However essentially having every job possess atleast 1 DoT ability is overusing the mechanic. I feel like a number of the 1 off DoT's possessed by most DPS jobs could go away as they kind of just feel like a filler unless its built into an actual debuff that applies another effect along with it. Perfect examples of this type of debuff are seen in FFXI with Dia and Bio. Dia caused DoT but also weakened enemy defense. Bio caused DoT and also weakened enemy attack.