CNJ was able to tank in certain situations before, though not as functionally as a GLA or MRD, and certainly not comparable to PLD or WAR. But of the cross-class abilities that allowed CNJ to have survivability to tank, WHM only loses Sanguine Rite and Decoy--Sanguine Rite is the biggest loss, but the addition of Regen could probably make up for the HP not spent curing yourself. You also gain access to Presence of Mind, which can allow for back-to-back stoneskin. WHM could still tank situationally--and like I said, the letters are, to my knowledge, for macroing purposes, and if I can't set the tank to whatever I want, it loses most of its usefulness (as I said, as opposed to simply displaying CNJ, WHM, GLA, etc. next to the names).
That aside, you make a fair point that "WAR isn't a caster," but WAR can be a tank OR a damage dealer--so what of them? Will they display as TA1? :P