Damage per stack, based on 100 effective throwing wpf, 6 power throw, and 18 str, against 50 armor (typical cRPG player):
Francisca: 44
Throwing Axe: 48
Heavy Throwing Axe: 42
War Darts: 84
Javelins: 64
Jarid: 83
Throwing Spear: 97
The axe line is a joke compared to the spear line. I know axes have a few advantage over jarids (better melee mode, slightly faster, more favorable hitbox), but these minor advantages don't outweigh the fact that they do HALF as much damage as Jarids, with significantly shorter effective range.
The devs wanted variety? Well, before the ammo nerf, people only used HTA and Jarids/spears. Now they only use Jarids/spears. If the objective was increased diversity, it was not met.