"All planets with the exception of Venus and Mercury have moons."

This is true, but there are moons and there are moons - and the difference between these types of moons points to another interesting distinction between planet types. Earth and Mars do have moons, but they are rather unlike those of the larger planets (save, to some extent, Neptune*).

The moons of the four "gas giants" (Jupiter, Saturn, Uranus and Neptune*) are thought to have formed at the same time as their parents, as part of the general conglomeration of stuff that came together in a local gravitational sub-attraction orbiting the early Sun.
*Neptune is an exception since it appears to have captured its large moon Triton after its formation, and the captured body's retrograde and eccentric motion disrupted Neptune’s 'native' moons.

Earth and Mars are more like Neptune's case. Mars captured the tiny asteroids Phobos and Deimos relatively recently, and those are predicted to crash into Mars relatively soon (in geological timescales). Earth apparently 'captured' a Mars size body so closely that there was a collision, with the heavy part of the captive falling into the early Earth's core while the lighter stuff went into orbit (with a portion of the early Earth) to eventually form our Moon.

So none of the inner planets appear to have had 'native' moons that formed alongside them, whereas all the outer planets appear to have had 'native' moons. Including Pluto. Pluto's moons are in circular orbits about Pluto's equator - a good indicator that they formed together (especially in conjunction with the fact that Pluto doesn't have enough mass to go around capturing moons willy-nilly). So in this sense Pluto is more akin to the gas giants than are the inner planets.

This “dominating an orbit” category for planet status does not convince me. Orbital resonance is a complex issue that is largely still beyond our computational abilities, but nevertheless there is an observed (approximate) gravitational resonance between Jupiter and Saturn (and by further association all the other outer planets).  If Pluto is "dominated" by Neptune in a resonance, then I think it's reasonable to suspect that Saturn is dominated by Jupiter (even if the computational modelling can't confirm it).

The reason for the reclassification is the realisation that there are probably loads of bodies out there bigger than Pluto. So, we either have eight planets and loads of "Kuiper belt objects" (Plutinos); or just loads of planets. Either way the "text books" will need replacing, so why not go for the easiest replacement route? Even though, as rickymaveety# indicates, the whole classification thing is an arbitrary exercise.

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"My astrologist went insane when he heard  the news...what will now happen to the scorpio-sign people?"

Heh, your astrologer was either already insane, if he genuinely believed in his "field of study", or insanely clever in convincing you of its veracity. Speaking as an allegedly "Scorpio-sign" person who was born while the Sun was actually in the constellation Libra, I can confirm that astrology is an utter load of bollocks.

 _

I'd classified rickymaveety as a bloke - rickymaveety's avatar challenges this classification. Is nothing sacred? :-)