1. The Republic has no concept of institutional checks and balances. Normally, if a head of state is able to override the unwritten constitution and prepare his world for obliteration by enraged God-like aliens, it would be safe to say that a given system of government has major existential issues.
2. As a consequence, the Republic is very unstable. It apparently isn't at all rare for major political figures to die suddenly, their body parts disappearing for unknown reasons.
3. As another consequence, after Vorlon visitation, the Republic is now short a fleet. There was a passing glimpse, as the Vorlon planet-killer approached low orbit, of the debris of a destroyed Centauri warship, apparently one of the ships sent to hold the line against the Vorlons. It seems that the Centauri's own version of the Battle of the Line ended badly. I'd think this would have serious ramifications.