tl;dr vaguely OT shitpost follows
At range, the asari justicar has warp rounds + power amp + area reave, an ability that swiftly deals enough DPS to stop a banshee charge on platinum, can't be blocked by the phantom bubble, and is further amplified by the fact that it stacks when a single user casts multiple times on a target. DC does not, each new cast by a single user cancels out DC's effect and it has no AOE. BE detonations from projectiles such as warp and throw can be dodged, thrown aside by the banshee hand of denial, absorbed entirely by groups of swarmers, or just flat out defeated by lag. Lift grenades are an inefficient means of damaging heavy armor or shielded bosses on gold and nearly all shielded/armored enemies on platinum, and more so on a grenade sparse map. And this is assuming the Justicar isn't capable of using the bubble strategically and anticipating where enemy spawns will move, all the skilled Justicar players I have encountered (I myself do not count as one) are more than capable of bubbling effectively at range on any map because they can anticipate the predictable AI paths the enemies follow and use the bubble accordingly at choke points. The sentinel is the weakest at range, she basically just has the single target warp + incendiary rounds, no AOE ranged attack.
At CQC Justicar should not have any problem staying alive without the shield drain gimmick (which, for the record, will not stop lethal damage in time if taking fire from the vast majority of plat enemies, enemies outside of the drain radius, or from multiple sources). Even when no evolution for additional DR is taken with the bubble or reave, she has 45% stacking DR , comparable to the Asari Valkyrie's 50% DR if tech armor is maxed (I've almost never put 6 ranks in Tech Armor for her though and don't think taking 6B is particularly worth it, either). Last time I played her, she had no trouble taking out 2 banshees and a brute at CQC/mid-range on platinum at a rate very similar to the Valkyrie with the quite rapid reave + bubble + reave combo. Last time I played her off-host, she also had no problem doing the same, whereas AF failed to prime, failed to drain, and forced a retreat. Justicar is superior at CQC to Commando and Huntress, who will be shredded if pinned by multiple platinum enemies in any solo situation and has low odds of detonating a BE or headshotting 3-4 enemies fast enough to hold their ground, whereas the Justicar actually CAN hold her ground against large groups so long as she's using the bubble smartly. I probably just need to L2P, but I have always had an easier time holding my ground against multiple rushing enemies in a solo situation (such as w7 cerb plat) with the Justicar than I have with the Huntress/Commando, so I believe in CQC she is superior to those two and comparable to the Sentinel.
Better at ranged combat then the Sentinel and Vanguard, comparable in CQC to the Sentinel and with similar "survivability", better at CQC than Huntress and Adept, vastly better boss DPS than the vanguard but still highly effective against mooks. Huh, seems like the Justicar is balanced for all encounters at any range versus any map or faction. But yes, without a doubt weaker than other Asari yepyepyep
I say this even when I do personally prefer the Commando in both teamplay and solos. Justicar is not the strongest asari, but she is extremely well-balanced compared to her asari sisters. I actually believe she is more versatile and interesting in various UUG and UUP* situations than the vanguard, the sentinel, and the huntress, but that is purely in the realm of personal opinion.
*note that i actually only play turians on bronze so just speaking in purely hypothetical terms here, i am a theorycrafter who does not actually play this video game extensively