Just got the Moonglaives, with COF and Moonglaives, should BC be delayed a few seconds for the Moonglaives to come off CD?
no, save moonglaives for the next BC. Unless it's literally like 2 seconds -- it's not worth risking missing an extra GCD in a fight usually.
If you're using BC correctly, the CDs of both BC and glaives should line up within a few seconds of each other.