There really on not many gotchas - yes you will lose your historical data - if you are using Distributed virtual switch you will have to rebuild it in the new environment but if your are not then you when you add the hosts the virtual standard switch will come in with the ESXi host -
After your new vcenter is built you will have to dismantle your old environment - I would do this by disabling any cluster DRS/HA and then simply remove the host from the old inventory and then add it to the new environment -