Originally Posted by Zatoichi
I'm not sure that's entirely true - in my ERE campaign the WRE are constantly destroying chunks of my Epic stone walls with saps.
Maybe you are not seeing it because the ability to sap is less prevelant in BI 'barbarian' units. If I'm seeing this correctly, it's now not possible to build saps unless there is a unit in the siege stack that has the sapping ability. (I need to investigate this some more, it could be more random than this!)
I'm enjoying the fact that sapping is more prevelant by the AI - in all my campaigns in RTW, I was sapped precisely once in the countless sieges I experienced. In a week of BI, it's happened 4 times - a very good improvement.