@Cleftobismal: You're misunderstanding the point everyone's trying to make.
WHM has slightly more healing than AST yes, but only very slightly.
Ghishlain made a perfect example. If WHM is an A+ at healing, AST is an A-. Hardly any difference at all. They both heal perfectly well as potential main healers.

The problem comes with everything after that. WHM simply stops at healing while AST goes on to offer some of the best utility in the game, and MP restore on the level of AST. That's where it's weird. If an AST comes so close to our healing power, they shouldn't offer so strong of buffs. It makes us seem unnecessary if another job that offers more can just fill out shoes.

With AST and WHM you should be making a clear and obvious decision. Do you wants buffs or better healing? You should feel safer and be safer with a WHMs healing, and you should feel stronger with an AST. You should be able to see a noticeable difference in the power of a WHM vs AST Healing power.