The "prohibitive" MP is there to prevent you from main healing a fight. At 1200 potency you're healing a bit more than Cure II can. For the purpose it serves (emergency heals), costing 40% of you MP bar is "acceptable". You also have ways to recover MP via Riot Blade and Sheltron. I think PLD can easily fit in 5 to 6 Clemencies in a minute.
WAR's DPS is vital to its kit. The original design of WAR is a drain-tank. While it was shifted to a mitigation tank, it still has gaps to fill through draining. Those gaps are: Less effective healing received. Slightly weaker CDs than PLD's.
I'm not saying WAR is weaker than PLD. The entire toolkit of WAR is strong. It's actually stronger than PLD's even in terms of mitigation. A warrior turtling hard WILL out-mitigate a PLD simply because of ridiculous uptime on some of their abilities. But turtling on WAR hurts its DPS massively since it involves certain GCD manipulation. But skill-to-skill comparison, WAR's abilities are slightly weaker than PLD. WAR has to couple abilities together to increase their effectiveness.
In short, WAR "needs" all that DPS. It IS part of their mitigation as tanks.
