I am inclined to agree, but then think of the asteroid belt in our solar system. There are man rather big objects in there and there are a few tiny dwarf planets. Where would one draw the line between dwarf planet and gigant asteroid? And there appear to be many more larger objects to be lurking beyond Pluto. Having more than 25 planets could indeed make our solar system a bit difficult for laypersons like school kids.
How about counting anything as a planet that revolts directly around a sun plus has an atmosphere or used to have one?
With this definition we could keep all the original planets*, exclude big asteroids and include the more interesting objects yet to be found.
Only Jupiter's moon Europa would cause difficulties as it does indeed have traces of an atmosphere. It's a matter of definition if we consider Europa/Jupiter to be a binary planet (after all there are binary suns) or if we exclude Europa, based on the fact that it's not immediately circling the sun.
*The upper layers of a gas gigant would count as atmosphere, imo,so that Jupiter would count. Mercury has no atmosphere atm but it used to have one, originally.