Personally, i think its weird to call a ice chunk in extreme epliptic orbit a planet, but pluto got a atmosphere, so i COULD be ok with either idea.
But, now they get into SERIOUS problems explaining eventual other solar systems: if a system got a loose gas giant, who orbits a 2. gas giant who is larger, you get a planet maybe 3-4 times as large as jupiter with a moon looking as uranus
when the depate were underway, i wondered what ID call a planet. my idea to a definition: a mass without natural fusion reaction in core, with or without orbiting a star. the size need to be large enough to have gravity enough for a atmosphere, regardless if it got one.
of couse, my definition would even cover artificial spaceships large enough.