I have a question about the WJ build, is the 2 points in Fanaticism nesseary to maintain good force management or can you get away with 1 and then 2 in Claws of decay for more thrash damage?
Yes it is completely and utterly necessary to take 2 points in Fanaticism
Do not ever take points in Claws of Decay/Insulation/anything over it. If you're playing the spec correctly (more or less using Death Field on cooldown) you will run out of force very quickly without 2x Fanaticism. And if you find that you aren't running out of force you aren't playing it right.