Can confirm alacrity got really stingy with the last patch.
Tested it out and only hitting your target within 360 range will grant alacrity, although I have a hunch even this sometimes doesn't work properly. I've had fights where I barely received any alacrity and I'm somewhat pozitive I was in range, but I might be wrong.
The skill tool tip still has the range labeled as "Ally Boon Radius", not "Boon Trigger" or something, so I hope it's a bug and not intentional - it feel pretty bad.