User blog comment:Master Sima Yi/Assassinews 12-05-'15 — Assassin's Creed: Syndicate has been revealed!/@comment-5174994-20150512182658/@comment-5174994-20150512183425

Kab, I just read this quote which basically implies that they're waiting until E3 to reveal her:

"Evie is a presentation that we are going to save,” says Pelland, perhaps eyeing up a bigger audience at the huge E3 games event in June. “When we focus on her, we’ll really focus on her,” he assures."