The issue isn't with Shield Oath or anything like that. I tanked T9 and had no issues with enmity and have been going since the patch with no issues. The issue is with Flash it is a piece of shit ability that needs to be changed to properly scale with gear. Currently it only scales with level and nothing else. This means that a i110 Paladin tank generates the same enmity from flash as a fresh level 50 paladin with Artifact gear. As of right now Paladins are useless in the new dungeons or in any instance that you need to have them pull multiple adds. So until they fix the issues with flash take a Warrior into the new dungeons and you will have an easier time holding aggro.