I have been reluctant to use any Add ons, I enjoy the minamallistic UI; i do think the current base UI should be more informing as to when/what type of debuffs are on you. By either your character have more dramatic visual effects or by having your screen borders do different effects. (Bubble when poisoned, Fleshflies when diseased, burn when on fire, ect...) . If youre not using certain Add-ons in pvp you are at a clear disadvantage to those who are. Zenimax needs to add certain UI alterations that can off set the need for add-ons, the ability to differ players in pvp like the rainbow retical type mods.
I know some Add-ons are helpful, Zenimax needs to adopt certain ones and add them to the game for everyone. Even if you can toggle them on/off in the settings.