Let me clarify - I 100% agree that Aura's as passive buffs is boring and non-engaging design. I'm not entirely sure HOW I would design them for PVE, and in my build I made years ago I honestly didn't even considered it because as you've indicated, mechanically they're just not interesting.
However, I did find some really useful applications in PVP (below is a snippet I pulled out):
Keep in mind that in this build Divine Storm is a resource draining toggle ability, not like it is on live.
Unstoppable Vortex
"Divine Storm costs 50% less Mana per second to maintain. In addition while it is active any allies inside the effect take 30% reduced damage unless enemies are inside the storm's radius."
Mirror of Vengeance
"While Divine Storm is active all harmful effects are reflected at their casters (Note that direct damage will go through, but effects such as Frost fever, Polymorph, etc. will be reflected). Effects cast from inside the storm's radius are not reflected." Reflected attacks also generate Rending Light stacks."
Revitalizing Tempest
"Your Divine Storm heals you and your party members for 100% of the damage it deals."
This tier empowers DS. I wanted it to be both a defensive ability and offensive. Given it's cost to maintain it needed to have very strong effects.The static 30% damage reduction gives incentives to make sure that melee targets are tasked to dispose of the Paladin instead of ranged. Mirror of Vengeance is great because it really punishes spellcasters for blindly throwing debuffs at the Paladin. it gives a risk vs. reward to get close to get meaningful effects off before retreating. Revitalizing tempest is designed to bolster your allies desire to stay in the fight. This is especially effective against melee cleave comps where debuffs or ranged attacks are a non-issue.
If you look at these abilities I feel that you can see the theme I was going for. It's that the Paladin is the center of the fight. They inspire and lead and are threatening, but not always in direct manners.