Flare is a basically terrible power, especially for the Adept, for several reasons:
* Anything it can do, your innate powers can do better. Your existing powers and combinations are capable of inflicting exponentially more damage in a vastly shorter recharge time.
* It has an obscene base recharge time. Even with EVERY recharge speed bonus in the game it still takes roughly 5 seconds to recharge. Not only does this make it an inferior detonator power compared to Throw/Shockwave/Cluster Grenade, but by taking all those power recharge bonuses you must skip out on power damage bonuses---which defeats the purpose of using a high damage power.
* The only damage multiplier it receives is against shields and barriers, and that is only with said evolution. This means the only time it is 'worth' using for pure damage is when you make first contact with an enemy. Doing so then leaves you recharging your powers longer before you can finish them off. In contrast, comparable shield/barrier damage can be unleashed with one shot from the Acolyte, or a Warp + Cluster Grenade combination.
I took a moment to reset my Adept's powers and alternate her armor to maximize power damage bonuses (see below), then I walked into the Armax Arena against Reapers on Insanity. Here are the comparisons:
BRUTE
-Flare destroyed 1 out of 10 bars of armor
-Warp followed by Throw destroyed 6 out of 10 armor bars, once the Warp damage over time concluded
-Warp followed by a five shrapnel damage combo Cluster Grenade destroyed him completely
MARAUDER
-Flare left him with 1 bar of health, presumably with the few power damage intel upgrades I am missing it would kill him....as long as it is not dodged. In any event your existing selection of powers would kill him more efficiently and with faster cumulative recharge time.
RAVAGER
-Flare destroyed 1 out of 10 bars of armor.
-Warp followed by Throw destroyed him completely, once the Warp damage over time ran out
BANSHEE
-Warp followed by Throw destroyed 9 of her 10 barrier bars. A repetition of that combination destroyed 4 out of her 10 armor bars. While I did not test Flare it is safe to conclude that it would have inflicted noticeable barrier damage, and negligible armor damage.
Here is the setup used:
6 Warp [Detonate, Expose, Pierce]
6 Singularity [Radius, Recharge Speed, Detonate]
6 Throw [Force, Detonate, Double Throw]
4 Pull [Radius]
6 Cluster Grenade [Damage, Damage Combo, Shrapnel]
6 Shockwave [Radius, Detonate, Lifting Shockwave]
6 Biotic Mastery [Damage & Force, Damage & Capacity, Power Mastery]
6 Fitness [Durability, Barrier Recharge, Melee Synergy]
6 Flare [Damage, Detonate, Shield Damage]
Armor: Serrice Council and Umbra Visor [+50% Power Damage]
Weapon: Acolyte X [Pistol Power Magnifier IV, Melee Stunner V]
Relevant Intel Upgrades +15% Power Damage
With that setup I have the following bonuses (and sources)
+70 power damage and force (Biotic Mastery)
+50 Power damage (armor)
+25 power damage (weapon mod)
+15% power damage (intel upgrades; not all choices were damage)
P.S. Before anyone chimes in with the mandatory "power damage does not affect biotic explosion damage" response, know that I am more than well aware of the mechanics of power combinations. The purpose of power damage bonuses here is to bolster the individual power damage of Warp and Cluster Grenade, which are then multiplied by their respective evolutions, either directly (Pierce) or indirectly (Shrapnel). Insanity in single-player is equal to Silver in multiplayer, which means enemy health/armor etc is low enough that sheer power damage alone makes a significant contribution to the total damage needed to finish off a target.