/sigh
Again you have tunnel vision and can't see past the simple numbers. You are obsessing over minor things and totally ignoring some major ones. Being able to toss a cure 4 that does 420 compared to a cure 4 that does 460 or 470 isn't that big a deal. It just isn't...
The fact a Paladin can melee very well with a staff and use spirit taker to recover his mp for example is a real advantage. The Paladin has a native mp pool and can get up to +4 mp a tic from just gear and his job trait alone, not even counting the refresh spell or sublimation from support jobs, not to mention having a good defense as a healer is in itself a benefit, as cures create quite a bit of enmity. It can also add defensive buffs such as phalanx to the tank, making them take less damage to begin with.
Bottom line is Paladins don't suck at healing. I don't care where you place them in your imaginary totem pole of healers. They can get the job done in the vast majority of situations, and that's what matters in the end. Not 10 or 20% more cure potency on a piece of gear or w/e silly rank you want to give them.