"Sir, we have the goblin general on satelite".
"Very good, send some cruise missiles and take care of it".
With all due respect to our military forces, I think recent history has shown that our modern imaging techniques are not particularly good at finding particular individuals who don't want to get shot or blown up - those still seem to require more mundane intelligence gathering techniques.
Let's assume, however, that the horde leader isn't trying to hide from satellite imagery. It is still very difficult to identify individuals, and there's a delay between when you snap the picture, and the arrival of the munitions - and individuals tend to move around.
But, more importantly, you're the head of a fantasy horde - that means your pretty badass (have lots of hit points, and maybe Improved Evasion) and you fail to be stupid. You've got powerful spellcasters, and are used to looking out for the enemy sending dragons and whatnot. You're telling me you don't have folks keeping air elementals and the like in the skies whacking anything bigger than a goose out of the sky?
Also, since many world leaders have those underground bunkers, would scry even be able to find them?
Nothing in the d20 SRD spell description says it'd be stopped by any particular material.
Actually, given the modifiers to the scrying rolls, it would have a powerful but delayed impact. They'd have to get some actual intelligence on their targets first if they wanted any real chance of succeeding at scrying...and its not like a goblin could just walk into a bar and casually chat someone up, "So, tell me about this...Oh Bar Mar...who leads this country. He sounds a fascinating hum...man"
Knowing nothing about him makes it a +10. But even having secondhand knowledge (like a newspaper) makes it only a +5. Getting an image of him (see again, that newspaper) puts that down to a +3. The newspaper won't have a lot on generals, true. But actual national leaders should be pretty easy to find.
And that's before you get to using any other divinations to get information about the targets.
And that's still assuming that magic works perfectly in our world... What if Alter Self just made you look like Lemmy Kilmister? Or Teleport worked more like Blink?
Well, then of course magic loses. The discussion is trivial and uninteresting if either side is significantly nerfed.