Kingdoms are actually very different from Factions.
I believe you can't place/break core in Factions right?
According to your "Replace it with factions and that would maybe he 30% more players."
In my opinion that it will not help us get more players. For me, if I joined
CubedCraft for the first time I will not choose to play Factions
since it's same on all Minecraft Servers.