I usually say that this issue doesn’t matter, but i’truth I would have preferred a different ruling from the IAU, for three reasons:
a) The third criterion means that you can’t determine whether something is a planet until you have thoroughly observed, not just the planet, but its orbital environment. For some scattered belt objects this could take decades.
b) The third criterion is not actually all that clear cut. Earth, for instance, has not completely swept its orbital area clear of planetesimals, and every few million years one of them collides with Earth. It is possible to parameterise this property statistically but you still end up having to make a call on how clear is clear enough.
c) Unless it is unavoidable, I think that scientific jargon should avoid using common words in a way that is at odds with their common usage. It would have been better to reframe the definition so that the category “planet” at least included all of the objects that were commonly called planets (and you could do this by leaving out criterion III), or (probably better) just give up on the use of the term planet as an astronomical term of art.
It is similar to the discussion regarding birds and dinosaurs.
Some background: Cladistics is an important trend in modern zoological nomenclature and categorisation. A clade is a group of animals defined as a particular form plus all of its descendants. It is very useful for zoologists to deal with clades, rather than non-clade categories, particularly since the rise of techniques for genetic comparison. It has long been known that all modern birds descend from therapod dinosaurs: for a zoologist, there can be no sensible category that includes all of the dinosaurs but not modern birds. For instance, velociraptor is closer to a modern bird than it is to most dinosaurs: in terms of ancestry, in terms of morphology (feathers and hip-shape), even in terms of chronology (it is 75 million years from modern birds, but lived more than 100 million years after many dinosaur groups died out.) And so it is that the clade Dinosauria includes all dinosaurs and birds.
Which is all well and good, but this is now also reflected in works aimed at a general audience, as a change in meaning of the word dinosaur. The Wikipedia article on dinosaurs has an info box showing dinosaurs living from the Triassic up to the Present, which could baffle or even mislead a casual reader. If they go on to read the article they’ll find out that birds are dinosaurs, which might make them thing zoologists are in the category “weirdos” and science is stupid. Some authors fastidiously use the term “non-avian dinosaur” if they want to refer to ye olde timey dinosaurs.
My view is that it would be better to leave the ordinary word “dinosaur” as it is, and use the jargon term Dinosauria if you want to refer to the clade: accept that zoological category words used in general communication need not be clades. It seems my view is not the common one, though, with specific regard to dinosaur/bird. It is odd because in other cases, authors are happy to let it slide. It is known that “reptile” is not a category that represents a clade, and there are various discussions about how to redefine (or abandon) the category Reptilia, but technical authors seem quite happy to use the term reptile in its normal range of meanings when writing for a general audience.
EDIT: I have made an additions, shown in bold. For some reason, I neglected to finish that sentence, previously. Also, culled a needless ‘either’. Try saying that: “needless either”. There’s some cheap fun.