Be very careful with only going 3 into blessing. Yes, the damage increase is minimal by ranking it up, but the # of hits also increases by 10 per rank.
A level 3 blessing with full attributes will only have 50 hits before it dissipates. Most classes will blow through that easily within the 35 second cooldown of the skill.
You are leaving a ton of damage on the table by not getting it to 5-10. I would recommend getting it to level 3, and then seeing how long it takes before you lose the buff. From there, level it up accordingly so the buff lasts the full duration of the skill.
EDIT: Also when you are in groups, see how long other classes take to lose the buff. Wizards and Archers will blow through the # of attacks much quicker than you.