Personally, I wouldn't mind if WHM got Haste but AST and SCH both already have abilities like it (Arrow and Selene's Fey Wind), so it's not really helping differentiate the jobs.
You're idea for a Water II spell is good but please no knockback effect, it would be unbearable. >x>
One change I would like to see is with Stoneskin II. I would suggest turning it into a oGCD ability, instant cast, and have it useable during battle with either a 60 or 90 second cooldown. This will give it mitigation and some utility.
I think one of the main problems with coming up with ideas for unique skills is that WHMs in past FFs have always been the straight-forward healing job, even in games that present additional healers. Even in games were they have buff and debuff spells, the spells are generally pretty straight-forward, increasing or decrease main or secondary stats or mitigating damage, both things AST and SCH already do in this game. They also had status effect spells but almost all of their usual status effects are already in the game as boss mechanics.
For me, I think looking into upping WHM's damage, giving them more ways to heal while in Cleric-Stance, and fixing their MP issues while DPSing is they way to go.
