Any reason to remove this field? Thought it is a regression.
Most of the time we need a Ordering Contact which usually is default in v6.1.
If it's a service type sales order, we usually only need a ordering contact, much more important than shipping or invoice address, to be printed in rml report, etc.
Hope there will be a complementary module to retrieved this useful field back! And return in V8.0.
It is a must have for old user of OpenERP.