You *need* Invigorate for sure. You will have TP issues, and no, singing Paeon isn't going to be ideal in most situations (so don't start relying on it; you will need to sing Ballad and Foe's most of the time when you sing)

Blood for Blood is also very important. 10% damage boost with pretty good uptime is very helpful, especially in burst situations and during DPS checks.

So yes, start leveling LNC.