And in my opinion the play order is very important.
Yes, especially if you play an empire late in one epoch and can play early (or first!) in the following epoch, you can maximize the value of your holdings. E.g. if you play Russia in Epoch VI after playing the Mughals in Epoch V, you will be able to score everything you held at the end of Epoch V as well as any gains you achieved as Russia on your current turn.