Q; Since there were, according to Troi, thousands of people on Aldea, why did they only abduct seven of the children from the Enterprise?
A; It would seem to be because these seven, according to the chief Aldean, are "special". Quite what they mean by this exactly we are never clearly told, but we must remember that they scanned the Enterprise in its entirety before choosing this particular seven to abduct. I think myself we can fairly assume them all to be reservoirs of talent, some obvious, like Wesley, and some less obvious, like Harry with his hitherto unsuspected talent for sculpture. It is probably significant that Katie, the musical lass, was partnered to the planet's boss muso: I mean, we're not talking third fiddle, second row of some obscure philharmonic here, we are talking grand fromage of toute le monde, and this is presumably not to be taken lightly.
Q; How come everybody but the Federation has a cloaking device?
A; I dunno. How come nobody but the Federation has got an android? Actually, I was being flippant when I wrote this, but go to Season Seven and check out the episode called 'The Pegasus' for further info. on why the Feds have no cloaking device.
Q; Why has the planet Aldea's position never been calculated by measuring the effect of its gravitational pull on other nearby planets?
A; Guess there ain't no nearby planets!
Why, I wonder, when the future of their species was at stake, were the Aldeans so damn polite about it all? Why didn't they just take the kids and then recloak? What could anybody have done?