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 Ongoing IAU discussion? 

Is the reason that there was no improved IAU definition of planets that they wanted to pass such a decision with a large majority, but couldn't come to an agreement yet? I hope it's not that they think the current definitions are OK, because they're clearly not. For example the definition of extrasolar planet states the lower mass limit for an object to be an extrasolar planet is the same as in the Solar System... but there was no such limit given. Neither for dwarf planets nor for regular planets. There would have been no harm done if the upper limit for extrasolar planets was also applied to the Solar System, but that wasn't done either. It's like they're hiding everything behind smoke and mirrors and make up the results as they go.

It would be relatively easy to come up with criteria that could decide if a newly discovered body is a planet or not. But they didn't do it. Why? What for example is wrong with the following?
1. A planetary mass object is an object with a mass between the agreed mass limit needed for hydrostatic equilibrium (5×1020kg) and the agreed mass limit needed for deuterium fusion (2.5×1028kg). (Both limits might be set lower since the first would exclude Pallas and Vesta which are remaining protoplanets and the second doesn't take into account that objects with high metallicity could allow deuterium fusion at a lower mass)
2. A planet is a planetary mass object on an orbit around at least one star that also has the capability of clearing its orbit (per Stern-Levison criteria. The difference is you only need to know mass and orbital period of the object (and the star of course), whereas with Soter's criteria you'd need to know everything about the system).
3. A dwarf planet (I prefer mesoplanet) is a planetary mass object on an orbit around at least one star that doesn't fulfill the Stern-Levison criteria.

More definitions could be added to account for other types of planetary mass objects. I prefer ""planetar"" for those that don't orbit any star - regardless if they were formed by themselves or in a system of which they were later ejected. Also, I'd like ""moon"" to mean a planetary mass object that orbits a planet (since the prototype object Luna is just that) - smaller bodies would just keep being ""satellites"". (If you don't like to have 60 planets of which most are small, why would you allow 60 moons of which most are tiny?)

Any ideas why the IAU doesn't come up with something like that?   

First of all, there is a lower mass limit: hydrostatic equilibrium. Second, this has nothing to do with improving the article. Simply talking about the merits or lack thereof of the IAU's decision is outside the scope of Wikipedia. podous 
Your second point is right. My opinions are not relevant, as I'm not an astronomer, and my conclusions from the available data would be OR, so neither belongs in the article. But you don't seem to realize that your first point is extremely open to definition. It could mean the shape of the object. Then the next question is where the limit between spheroidal and irregular is. It could mean an object with this mass and composition would certainly reach hydrostatic equilibrium. Or it could mean an object with this mass would certainly reach hydrostatic equilibrium. I'm heavily in favour of the third, as it is the one that could be most easily checked (especially for exoplanets), and avoids the problem that an ice world could qualify, while a larger and denser asteroid would be rejected, since rocky worlds are much harder to pull into equilibrium. But from statements in the article, I'm guessing at least those astronomers favor the second one. (And if they're not representative, why would they be in the article?)Basically, I want to say that the IAU should make a decision that makes it clear the astronomers know what they are doing and want to share their knowledge with the public. Because if the public decides to not follow astronomers' findings anymore, the result will likely be even less funding... and that would be a real problem.    
There are many ambiguities with the current definition, all of which are mentioned in the article already. podous 13:29, 19 Januar