What's the status on this? I'm using the latest nightly to date, and reactions don't seem to work very well for my guys.
I can get reaction-fired upon by a Sectoid for so much as kneeling (on Veteran), but it's really hard for my men to surprise an alien with any kind of reliability.
Reaction fire was crucial in the original game, and not only for door camping. A good portion of my kills in it was due to it given how I advanced across the field carefully, using scouts and HWPs as spotters and keeping many shooters with TUs so to deal with enemies that would come into range. Active, manual, spotter-aided firing was only half of that strategy.