The primary issue here is just how much more reliant our total dps is on our burst windows when compared to DRK and PLD.

Top parses show WARs with ~33% of total damage coming from FC. Since FC is rarely used outside of Berserk windows, we can assume that most of FC damage is done during zerk windows. Now consider that FCs account for 75% of the potency during a 6 FC window (3000 out of 4000 pot), and 48% (1500 out of 3100 pot) of the non-IR zerk window. This means that FCs account for 62% of damage done during serk windows on average.

If FCs account for 33% of our overall damage and FCs account for 63% of the potency during zerk windows, then that means ~55% of our damage comes during Berserk windows.

This all adds up to make WAR's damage very brittle. WARs do fine when battling a damage wall without mechanics, but if anything messes up our Berserk windows, our damage suffers considerably more than the other two tanks.