Why is there only 1 type of village?

In AoM and AoE:3 the various civilizations had quite a bit more diversity when it came to the villagers. Do you think AoE2 could benefit from these ideas?

• The Atlantian had a better gathering rate and a mobile drop off point.
• The Norse had a combination of a builder and military unit.
• They also have two types of gathers along with a mobile drop off point unit.
• Probably more...