Is assaulting Bunkers too hard ?

[wiggum]

The assault system (or the bunkers) itself isn't the problem, the problem is each unit having to disrupt which can make small units more resilient than they should be.

So what do you think can/should be done to tweak this ?
If disruptions and broken status would hit small units that take casualties faster then currently then i think it would be easier to have 3 or 4 small units inside a bunker hex disrupted/broken and a assault will be more likely to succeed.