Couple of things that would've made it very difficult to carry inventories over to the new server are:
Fully global balances. On OmniEarth your global balance is your balance. This means you can now buy and sell while offline.
New Inventory system. Instead of using a custom method to save your inventory we now just use Mojang's method. Inventories are still "global" (assuming there are multiple servers) but they are also now more resistant to change.
That's all for now, There will be more information in the coming days!