So this is my first playthrough with Ashley at the Loud DLC Citadel party and wow is the conversation on the balcony super awkward without Kaidan there. If Kaidan is at the party you have the three biotics there arguing with Vega, Biotics vs Soldier. I thought it was going to be interesting to have Ashley there as another person to argue for Soldiers, but she just leaves Vega out to dry and then sarcastically calls him "hombre". Seemed like a missed opportunity for the writers. Now, I am playing as a sentinel, so I defended biotics. Not sure if maybe Ashley just takes her cue from you and just supports whatever direction you go.
P.S.: Decided to load the party up again and then just see what happens if you support Vega. Ashley says even less in this version. Shepard makes a quip about a peak physical specimen before him, and everyone is talking about him meaning Vega. I thought that Shepard would then say he was talking about Ashley (romancing her this playthrough as well), but nope he's talking about Vega.