What were some challenges of imperial expansion of the roman empire?

Here are 8 reasons why Rome fell as an Empire. Turn them into challenges for your

1. Invasions by Barbarian tribes;
2. Economic troubles and overreliance on slave labor;
3. The rise of the Eastern Empire;
4. Overexpansion and military overspending;
5. Government corruption and political instability;
6. The arrival of the Huns and the migration of the Barbarian tribes;
7. The spread of Christianity and the loss of traditional values;
8 is important... See below
8. Weakening of the Roman legions:  Rome’s military was the envy of the ancient world. But during the decline, the makeup of the once mighty legions began to change. Unable to recruit enough soldiers from the Roman citizenry, emperors like Diocletian and Constantine began hiring foreign mercenaries to prop up their armies. The ranks of the legions eventually swelled with Germanic Goths and other barbarians, so much so that Romans began using the Latin word “barbarus” in place of “soldier.” While these Germanic soldiers of fortune proved to be fierce warriors, they also had little or no loyalty to the empire, and their power-hungry officers often turned against their Roman employers. In fact, many of the barbarians who sacked the city of Rome and brought down the Western Empire had earned their military stripes while serving in the Roman legions.

These are taken from History Stories, by Evan Andrews January 14, 2018.

Countries of eastern europe.