What are the challenges you face in Business Process re-engineering?

You need continuous search for critically examined and fail safe deployment of innovations in business process re-engineering. Failure rate of50% is not an acceptable term. I will not recommend pratical worthy any change- risk in excess of10%.

The biggest challenge is that there is no as-is measurement of KPIs & SLAs.
Hence there is no recognition of pain points and need to improve.
As a result most of the technology initiativies end up satisfying 'wants' rather than 'needs'.