Fey blessing is pretty useless atm imo. Not saying it's a bad skill though. Since Ruin II isn't that good your ogcd "space" is limited and fey blessing will often not make the cut when considering what to double weave. Mostly, because the healing requirements are still very low in the content. It's also outshined by the rest of your kit because we don't have a stack dump.

Otherwise it's pretty good for a topoff and I can see it scaling well with gear. It will enter full bloom if we get a dump back. Right now it's mostly about "can I use indom/soil now even if it overheals instead of blessing" and the answer is almost always "yes" so it goes unused.
I've personally only used it a handful of times. That's less than dissipation which is godaweful atm but still has some use in dungeons with crazy squishy tanks and large pulls.