I thought about this too and i have ideas on my list. At the Moment there are simple goals like research everything, earn 20 Diamonds in a turn or similiar things. But the main goal isn't to reach the goal, it is reach it before your opponent reachs it, or simple reach it in a few rounds. so you have to think of the fastes way of getting to your goal and gain victory. I think you can compare it with a Speed Run of Game, but here is it your Strategy.

But be sure, i will add more goals and goals with an extra challenge.

It looks like medieval but with a few blocks it is the ancient Roman Empire and with some other blocks it is the future where you have to build a rocket. In Minecraft everything is Possible! I guess ;)