They shouldn't be deleting a more expensive troop with a click.
What about their current stats suggest they shouldnt be? Lets crunch the numbers.
Every throwing spear has between 60 to 70ish pierce damage. Pierce damage ignores the most armor of any damage type.
Headshot multipliers are a big deal. They can be upwards of 1.5 to 2x damage. so that 60-70 damage is now 120-140 damage on headshots. All Heavy inf have 100 health, so we are well clearing that threshold of being deleted in a single click. Even with an absurdly large armor save of 50 or 60 damage, that heavy inf is still completely blackbarred and a single hit away from death.
Its worse on horseback. As you know, the game has modifiers in place to calculate damage based on relative movement speed. Running straight at someone who is running at you will yield damage numbers much higher than what is expected. This is a good mechanic in most cases, as it adds true weight to cavalry charges, and either punishes or rewards all in plays with insane damage dealt or taken. In the case of throwing spears, you can see upwards of 150 damage on bodyshots when running straight at someone and landing a direct blow on the body. With the headshot modifier added on this can and has easily surpass 300 damage. Heavy cav deleted. In the case of hitting the horse rather than the rider, even with the headshot modifier completely removed, 150 damage is still enough to absolutely 1 hit most of the horses in the game.
So that leaves the dev team with 3 options. They can either completely rewrite the games armor penetration, damage, speed, and headshot modifiers so that the ^^^^^ above is no longer how the game works, which will no doubt have consequences for every other weapon in the game.
They can nerf the Throwing Spears to like 45 damage, which would just result in a bunch of poles longer than the player characters are tall sticking out of everyone, looking absurd.
They can just replace the freaking things with regular javelins,
They should have the a significant advantage vs Archers and Shock Troops,
^^^^^ which have the same role that they want the throwing spears to fill, except less RNG dependent due to higher stack amounts which result in more consistent damage.
Some classes like the Wildling can even go back to how they were, with a default spear AND a default stack of 2 javelins. Letting them fill both roles of the throwing spear without all the stuff I listed above.
EDIT: I actually hopped on Bannerlord and checked the damage of throwing spears. 60-70 is too low. They actually have a default damage of 77-87 depending on the spear. So even more damage than what my post shows. So basically I accidentally proved that you could nerf the spears by 20 damage and they would still be broken.