During my time at InComm, we have gone through several organization changes. When big changes are made, employees tend to respond a little chaotically. I believe management needs to make sure to keep communication flowing between teams to ensure that teams continuing working together the way they need too. This isn't necessarily a con, they are communicating but with so many people the message gets lost.
Luckily, the company hosts a town hall to try to keep employees up to date. This resolves some of the chaos, but people are still taken back and during the change it gets a little difficult.
Pros to the con -- positions are opened up within the company.