Perhaps he's just much better at working in the shadows than Oliver is.
That might've been credible a few years ago, but no way would Batman have sat out an alien invasion.
Possibly, yes. But Helix seems to me like it's something a lot bigger than Prometheus, and that it's more about giving Felicity her own arc independent of Oliver's.
(Plus Mini-Felicity is pretty cute and I don't want her to be evil.)
It's not unusual for Canadian-made shows to leave out one or two cast members in certain episodes to save money, but it's usually just for one episode at a time -- e.g. one episode leaves out one actor, the next leaves out a different one, etc. A sustained absence like this, one that isn't plot-motivated and has the writers needing to make excuses for why she isn't seen on camera, feels like an attempt to work around a real-life absence.
