That is complete and utter crap. If anyone is having delusions of Grandeur it is you. WHM's had just fine MP management, at least the good ones. WHM had great MP management mostly because at the time Regen was very potent. Unlike todays game they were the primary healing spells cast.

As for PLD not being useful, are you crazy? it was the most practical tank on the majority of mobs, especially after the updates it got to put it above NIN. In both cases it wasn't about healing magic it was about uptime of shadows (haste slow and paralyze) and statically regenerating the players health (regens) allowing the PLD to do big heals on itself for additional CE.

(this is why RDM was the best overall tank until it was nerfed.)

WHM was and always has been the best endagame healer. RDM was brought to supply haste/refresh/slow/paralyze/dia. That is it. Anything a RDM did after that was determined by the RDM's opinion on what the group needed most. Endgame always had WHM's because they were the best healers (Cure V and Regens).

And endgame was done many ways, from the full group (tank party/dd party/mage party) to the zerg (DRK with Kraken/BRD/BRD/COR/RDM/WHM) to mana burn (BLM BRD COR RDM)

This is what endgame consisted of, and the only case that didn't include WHM as the healer was Manaburn mostly because players would log hate.

As I said clearly you have not done much endgame, WHM was the king of healing and every endgame group had one. With the exception of nyzul (until /SCH) which was basically a roaming exp party except on boss floors, that contained bosses that were susceptible to enfeebles allowing a RDM to be able to heal them successfully.

Your memory is either failing, or you are talking out your ass. RDM was never a replacement for a WHM in serious endgame.