I actually really liked the terror health regen mechanics and believed at the time that it would be really powerful for characters, but then the gear was quickly outleveled. When the Halloween DLC comes around again this year, it will be really interesting to see what builds players come up with.
I ran a Rakk build with a Transformer with terror, a grenade with terror health regen, and a Lyuda with terror ammo regen. Obviously that build would mot work at Mayhem 10 now with the way the Lyuda’s damage has become outclassed, but the concept was cool and could be moved over to different weapons to be equally powerful.
There is still a lot of potential with terror anoints that I think will be developed further this year during the Halloween DLC.