On the panel will be BioWare's Casey Hudson and screenwriter Mark Protosevich. You may know Protosevich from his writing credit on movies like Cell, Poseidon, I Am Legend, and the upcoming Jurassic Park IV. Thankfully he also worked on the story for Thor, so that's at least one decent movie under his belt.
No details on the plot yet, but one would assume Comic-Con would provide at least some information about the project. I'm going to wildly assume it will involve Reapers, Protheans, Mass Relays, and an intricate sci-fi noir story about Commander Shepard's corrupt practices while doing PR on the Citadel.
SDCC: Legendary Pictures Announces Line-Up [ComingSoon]