Is assaulting Bunkers too hard ?

[wiggum]

Isolating a bunker forces the defenders to stand and die and you're now at the vagaries of cleaning them out - better to get them in the open and shell them to death.

Or realistically - forces them to surrender.
I thought surrendering was abstracted into the assault casualties thats why these results feel odd.

Broken does seem to be a rarity, but in testing I've seen it happen pretty regularly when units have been pushed to the edge.

I dont know, a unit which lost 75% of its strength, is already disrupted and takes additional casualties and still not becomes broken seems the majority.
In Squad Battles Units could get pinned. In Panzer Battles there is Disrupted and Broken. Only broken prevents units from moving towards the enemy. I think it should happen a bit more often, currently units in PzB take a insane or unlimited (because broken status never occurs before the unit is completely eliminated) amount of beating before they bog down (broken status).