My personal opinion would be not treating employees as human beings. A merger can leave people feeling anxious and undervalued, and as a result they can fall victim to a significant amount of stress. Treating employees like cogs in a machine can leave them feel disenfranchised, unmotivated, and unsure of where they stand in the long-term.
Addressing these areas via appropriate people management and communication will go a long way to ensuring strategic goals are met, as without employee buy-in, integration efforts can be severely hampered.
