Is assaulting Bunkers too hard ?

[wiggum]

Clearly you can do it that way.

But the question remains, should defenders below 10 men always be able to fight off a assault by 180 men ?
Is there something wrong with the broken status ? Should defenders that were already broken and took additional casualties during a assault become broken ?
Is it a good idea to give bunker hexes their own suppply source which prevents them from becoming isolated ?
Is the "Finishing Off" rule working correct and should it maybe get expanded a bit ?