Go do your research again. And then come back.
http://wiki.ffxiclopedia.org/wiki/Afflatus_Solace
Cureskin has a hard cap of 300, no amount of additional healing will grant a higher skin. It lasts for 30s, the only ones who realistically can make use of it are the tanks. Also there is no cureskin for curaga's, only single target Cure's.
Sacrifice has a really BIG problem, namely that you must then remove all those status ailments from yourself, potentially having the tank die in the process. The key block here is Erase has a really annoying /recast even on RDM. SE needs to create Erase II for multiple removes and make Erase a 5s recast instead of 15s.
I was waiting for someone to mention Auspice / Gain spells. Their useless in big fights, specifically VWNM's, like Barspells. White Mage run's in, starts to cast Ausc.. *BAM 2K AOE* White Mage is now dead. White Mage hits yes on reraise ... long animation ... rising from ground ... *BAM ANOTHER AOE* White Mage is dead again. VWNM's tend to go *HUGE AOE* -> Tier IV Ga or Ja -> HUGE AOE -> Tier IV Ga or Ja -> HUGE AOE -> Tier II AM -> HUGE AOE. Trying to get up while your within 15 feet of them is suicide, the tank has to pull it away potentially killing other people. Tractor counts as zoning and won't work. We've had our main WHM weakened for 15 min straight due to aoe spam, and this is without trying to cast barspells. Simply put, on anything that can aoe one shot a white mage, you don't use those spells on. And if they can hit my Red Mage for 1700 through a 380 point stoneskin, then they will one shot a White Mage.
So again we're back to ..
Cure V
Erase
-na
Seriously, you guys should be making arguments about stona if anything. Its the one status removal that we can't get /WHM or /SCH and there are some fights that removing petrification are key. But the fact that no one has actually mentioned it just leads me to believe people actually really want to just replace White Mage outright.