One thing I think should happen, that'll also attract a LOT of the highly experienced players from all over, is to create a single server that only holds ONE world.
To enter, you must have the Heroic Tactician award, have had at one point OVER 100K ABP, must have a forum alias or willing to get one, and/or whatever other requirements that'll prevent a LOT of people from joining. But, in which, Grepolis [yourselves] would extend the invite to this world personally through an Email or other means. Mostly, the requirements would have to be strict and selective as well. You want THE top players from everywhere under one roof. So to do that, you filter until you get that.
Anyways, have the settings be at;
Game Speed: 3
Unit Speed: 5
Alliance Limit: 50
Conquest
No Morale
5 days of BP
(I picked 5 so that everyone can get all antsy for what else I'm about to post)
Upon entering, player's can choose which area they want to be in (Preferably core oceans). As well as a tutorial guide explaining how this world will be different and MUCH harder than any world players have played in before (TT is WAY less, BT is way less, REALLY smart and strong people playing). And the goal of the world, is NOT to build WW (Basing this off US Server as idk any other way you could win a world right now), but to CONQUER AT LEAST 75% OF THE WORLD.
BUT, here's the catch:
The world will only last ONE FULL YEAR'S TIME. Unlike most that last roughly 2 years. If no alliance has controlled 75% + of the world, then it becomes a dual between the Top 2 alliances IF close (within 6% of each other), OR an alliance with a majority of the world and is above 6% higher than the 2nd place alliance, then that alliance with the controlling percentage of the world will win.
This will create a very small but VERY battle/war heavy world. A Perfect setting for those who live for the fighting and never sleeping.
Should be easy to watch over and oversee as again, small world, and mostly condensed.
Idk, just a thought. I think it's go over insanely well. But I don't know coding to the extent you (Grepolis guys) do nor would I even begin to understand how to get my example started. I just got the idea.
Edit: Oh and by "conquer", I mean have someone lose the game. Not colonizations. Actually Conquering people.