I only consider bursts to be within 1 to 2 GCD. The rest is just general pressure damage IMO.
Tomahawk is usually applied pre-burst so that the enemy can't kite the incoming burst, I personally value that more than using it as an additional burst GCD.
PLD 20% bonus isn't reliable IMO, you'll be at different MP levels throughout the game if you are healing and silence peeling. One hit at most is usually a good one though. It's down to personal preference.
Yes onslaught is 750 pot, fel cleave is 2000. Had to fix an error with the original FC on it's own at 2,500.
All in all I think WAR needs a bit more, at least upheaval back on the skill-set.