I Think could be nice to implement new features in order to differentiate tribes.
This idea start from the historical knowledge, and the obvious fact that travian kingdom is essentially based on dynamics of the actual travian legends, the diffence between them
require new implementation.
Romans
Romans are a fixed tribe, in game each tribe has his own pro and cons, in reality, romans had only pro and barbarians only disadvantage. However for romans i thought the possibility in relocating troops between his villages; and the share, for each village, of the reasearches, for example, romans has not to research imperian in each village, they need to research him in only one village, the same for smithy, every level-up in smithy, is a level-up in each villages, so a 10 levelled imperian in a village has the same level in all villages of the same owner
Germans
new characteristic of german is the possibility to relocate the village, in order to move near the border of a kingdom, (according to the nomadic life of german tribes during the decline of roman empire), relocating is possible expanding resources( depending to the village population) and require time, works as a settler, but more expansive and lower, the fields of new village are at the first level, the remaining build have the same level of the village before relocation.
Gauls
Gauls are described as a defensive population, however in game, especially in an early server and when you are alone, a defensive strategy is a losing strategy. I Think that soldied, often, was also farmer. For gauls i thought
the possibility to have more production with more defensive troops, for example, 1 phalanx gain 1 of wood, clay and iron, druider gain 2 of the same resources. With this implementation a defensive strategy is more possible and closer to reality.