Likewise, Citizen Autumn is either awful or does nothing, Citizens Sweat and Tears should both be annihilated, and depending on how much damage you can absorb, you can make the call on whether to destroy or leave Citizens Hammer and Summer. Eliminate Citizen Truth unless Dawn is flipped.
Tachyon is often a good hero to bring for Hypersonic Assault, Blinding Speed, and Sucker Punch (not to mention the always-excellent Lightspeed Barrage). Writhe’s damage mitigation, irreducible damage, and Umbral Siphon can be a huge help. Stuntman and Mainstay can be good to help eat Ongoing destruction. La Comodora has a number of tools that can be helpful, including Rudder in the Timestream to put citizens back from Dawn’s trash to under her deck. Wraith’s Infrared Eyepiece, or better yet, double eyepieces, can really help. And don’t forget that the Aurora doesn’t hurt Golems, Constructs, or Devices.
In summary: it’s good to bring high damage or penetrating damage heroes, ongoing destruction is very helpful, deck manipulation is extremely helpful though not required. Trash manipulation can be an exploit. Most importantly, choose whether to flip her early or try to avoid a flip, and choose which Citizens to destroy based on game state.
I think it’s no surprise your group wants to get the hang of her. Of all the EE villains, I think she’s the one with exactly the right mix of stuff in her deck to be both fun to battle and to feel like there’s an AI behind her. Those auroras always come at the darnedest times!