If you want to bring a fun spin to the resource collection, try bringing environmental destabilization to the table in an epic way. Its a full planet, so the looming threat of over extraction of resources makes (for an end game and makes) the end game more dangerous. First you could add predators that emerge from sectors of extracted resources puting your operation at risk. Then as more and more resources are removed a world could become unstable and a player's (possibly?) persistent "score" of resources could be at risk if they don't leave the sector in time at which point the world could end. To increase the risk reward you could make it easier to extract more resources near the end of a world. An end game can also allow you to better cap the number of players in a server since a worlds resources could act as a indicator for a cut off on letting new players join. This enables a bit of progression as well since new players could start with small worlds (shorter matches) and higher level players could choose to enjoy bigger worlds (longer matches, more players) with more resource extraction potential.
I've been pondering a casual world based MMORTS as well. Spherical maps are a great way to explore strategy on a wider scale with no edge of the map strategies.
Want to get rid of players dropping from matches because they're getting "owned"? Give players the option of surrendering to another player, a surrendering player becomes a military subordinate to the player that they surrender to, allowing them to continue with less losses but sharing a % of any resources they gather with the player that they surrendered to. This could allow a commanding player to issue objectives to other players that have surrendered to them and offer units, research, resource bonuses, etc as incentive for carrying out their commands. That way a newb doesn't need to always be matched with other newbs and can learn higher strategy from better players instead of just leaving a match because they keep losing.
