@Jay Rich: Berna is basically a panic button. Her evasion chance, HP + Defense affection bonuses, combined with Black rarity stats and the 1 sec initial timer on Assassinate 3 (combined with her own Assassinate chance up passive, especially after AW), as well as her low cost allow you to drop her in front of an enemy that made it past your primary blockers. She survives way longer than the other rogues, has a higher 1HKO chance, and can try assassination right off the bat. Her Skill AW (not yet in Nutaku) makes her Assassination attacks AoE, further enhancing her usefulness as a backup panic button (plus Block 1 means she won't actually block the other enemies, reducing damage taken while still attacking them and possibly 1HKO'ing them). Not someone you'd use often, but is useful when you need that panic button.
@ZeroZet: IIRC Sophie's Skill AW gives her godly stats but the skill cooldown gets much worse, Sherry goes from pure Attack Up to Charge Up then next use ranged 5-target murder, Shizuka goes from samurai to pure duelist (1 block, massive increases to attack and defense), Spica loses ranged bonus but her arrows become magical, Robert attacks instead of heals, Despara gets AoE at the cost of range and lower attack boost, Monica gets the hilarious Gatling Gun, Marius' becomes a mode switch (heal OR attack instead of only healing during skill). If I missed any whose role either changes or is significantly affected by Skill AW, I'd like to know.
Derailing current conversation to get back to Thread topic for a moment: I'm assuming this is just super shitty luck, but this morning I did 3 Spirit Rescue G runs in a row where I got 0 drops despite 3* on all 3 runs. Anyone else hit this, or did I just get bad luck? (like I said, assuming it's just the latter, but if it's the former... might need to tell Nutaku)