No matter what switches into the scout, any status the move inflicts should hamper the opponent's attempt to counter it. I am not sure why a Defensive down is the most useful secondary effect as it does not really scout anything at all and could lower the wrong Defense anyway.
Actually a move that lowers whichever Defense stat is higher would be cool but I like my submission so I will stick with it.
The purpose behind a defense drop is the threat of power. CAP7 isn't extremely strong, but it still has the capacity to deal heavy damage with stat mods. Scouting is helped most by the opponent losing stats rather than you gaining stats, though, because otherwise we're just sweeping instead of encouraging a switch, which really is the entire point - if we lower their defense, we can do more damage. The opponent doesn't want that, and is thus likely to want to switch out if their defense has dropped to keep from having whatever they have die. Saying that it would be cool to lower whichever defense stat is higher doesn't help us - CAP7 was voted to be very physically-oriented, so if their special defense is lowered, that doesn't encourage a switch.
In much the same way, your ghost-type tri-attack does not really encourage a switch, either. It can inflict status, which means they may want to switch to something that will mind status the least, but it can't do anything past that, because once something is already statused then unless it's burn on a physical attacker (done better by WoW, which we'll probably get) or freeze there's little reason for the opponent to switch out and possibly get something else statused, unless the attack would kill them and they want to switch to a wall. In that respect, it's little different from any other attacking move... And if it's just an attacking move, what's the point in making something new? We already have very viable 'pure' attacks in Shadow Claw for ghost and Iron Head/Meteor Mash for steel. We don't want this thing to be a real sweeper, so going at it from that angle seems wrong.
Of course, leer/screech effects aren't the only alternate effect that encourages switching - a few other rather useful things have been brought up, like ghost curse, which is pretty interesting. But there's really no point in making attacks that will solely be used on merit of damage, which is what your 'Pandemonium' would inevitably be used for. Of course, it's not nearly as bad as stuff like Ghost Earthquake or Ghost Brave Bird with Flinch or other incredibly ridiculous suggestions that go completely against the concept... But still, from my point of view, it's just not what it could be.
Since I've brought myself to the topic of other effects, I really feel that leer is the best effect to tack on for a variety of reasons, but the most important is that it's "weak" without being useless. Because it's easily removed and it will not usually cause a nigh-immediate loss, it can be tacked on to something with relatively high power with a very high chance of occuring. With things like status moves, or even curse, which can cause the opponent to absolutely have to switch unless they want to die, but are still removed by switching, the power level is inherently very high - it either cannot be put on a strong move, or it cannot come up often. This is contrary to the spirit of the design - there should be an obvious reason to use this move over other moves other than because you want to randomly gain advantage. Even with Screech, the activation immediately puts a lot of pressure on the opponent - there's a reason Screech doesn't do damage. Even with it lacking perfect accuracy, it is essentially just a better Leer. If we tack Screech on, it can't come up more than 30-40% of the time without perhaps being a bit too powerful. Not that there's anything wrong with that - that's not a bad design in and of itself. With Leer, though, it's not overpowered even if we do something with relative strength, even being more likely than not to cause the effect. With a scout type of pokemon, this feels like is the most useful thing to do. This is the logic behind my 'Soul Crush' idea - I feel it is best to pursue a combination utility/damage move, because it feels like it is of appropriate power level while also completely fulfilling the spirit of the design.
