I'll address your multiple "What about WARs?" points now:
PLDs and WARs bring different things to the table. PLDs bring utility and relatively safer pulls. WARs bring.. ..Damage.
Both are useful. Some pulls are harder with a WAR than a PLD. PLDs are generally better for speedruns because they can do pulls that WARs simply cannot, but both are useful and the difference in time between the two tanks is negligible, unlike the differences between the two healers. Unfortunately, WHMs are strictly better for speedruns.