Alright, I'll try to go in depth of how I wanted it.
Round Mode, would simply be like capture the flag, maybe a better example would be like Battlefield 2, only without the number of deaths to win. Basically, your team, red and blue for example, starts off with one base. There are smaller sub bases proceeding to each others bases that are capturable, and allow you to set a spawn there. Checkpoint mod maybe? Base plates would be the bricks you build on, anything on that baseplate is belongs to whichever team controls it.
Capturing would work like this:
1) The capturing team would need to step on a smaller plate (only 1 person), maybe 8x8 and control it for a set time. Can maybe be determined by mini game starter.
2) Any defenders on the plate cancel the capture, if they walk off, the timer is reset.
3) Once the base is captured, all enemy team units are killed or respawned at the closest base they control. If there are no bases they control they don't respawn.
RPG Mode, or maybe Conquest Mode, would be an ongoing thing. You would start the game, players would be asked to join or start an army/guild/etc, they would then be asked to pick a colour, from the palette of course, as well as a name for there faction. Teams would start in a random spot, maybe a default start location for each faction could be set, so spawn camping isn't too brutal. From there they would begin to take over castles. Teams would need to be saved, so that people can leave, come back and still be in there proper faction. Conditions for victory in this could be point accumulation, maybe make a score board that has the names of the teams and there current points. One team point could equal ten player kills, or half an hour of keeping the structure. You could set how many points it takes to win.
For painting the structure, maybe have a special brick paint option in the colour palette. Whatever has that colour will be switched to the controlling factions colour.