In another thread I asked what I hoped was a quick on-topic addition, but I'll move my question here.
In that thread Heighten was said to be a must-have feat. My experience with Heighten has been underwhelming; just a mana drain. Other level 20 healers have told me in the past to not bother with it... so I asked about that. Unfortunately I worded my question poorly and got a stupid response. My fault.
What I meant was, in what situations does Heighten make a "OMFG look at that" impact? What kind of experiment could I do to demonstrate and understand its "must have" potency? (For example, testing Maximize is easy; try BB with it on and off. No contest.)
As a healer in a party it doesn't appear to do anything.
Soloing Vale was really disappointing. Mobs didn't seem to die any faster. So I figure either I'm doing something wrong, it's highly situational, or I was just gullible and got sucked in by Heighten fanboys. Maybe all of the above.