I heard of that and can only say STUPID. Like WTF i like Pluto
The IAU needs to set a standard that isn't arbitrary. You can't have 'just pluto' as another planet without setting arbitrary conditions that, potentially, could lead to having several hundred (or thousand) objects being considered planets.
Previous to this, the only (recently) agreed upon factors of what was not a planet were
1: Any body large enough to ignite deuterium fusion, however shortly, is a brown dwarf
2: Any body too small to achieve hydrostatic equilibrium is too small to be considered a planet.
Between those two bounds are still over two dozen objects in the Solar System that qualify. That gets to be rather silly when several hundred are expected to be found. In the final agreement, it was chosen to make the definition narrow.