Same problems SMN with thunder have.
It is far less efficient than any of your moves (unless you're spamming Arm, which btw, never use except for the silence, or you NEED to get adds down immediately).
Stupid cross class skills D=
If it makes you feel better FR at least is the same efficiency as DK, and less than any of your other abilities.
...well crap that didn't actually make me feel any better.
Um...well...its...a filler...that uses less TP than ID.
Ahah! XD