Ok, from what I can tell the whole problem with [evil] can be shown in one spell:
Deathwatch
On the surface, for a good cleric, this looks like a great spell. Let's you know who is hurt and how bad, basically come up with a strategy on how to keep people alive.
I can see that. Looks good on the outside. But what is the spell actually doing? Let's not just look at the ends and say "Oh that spell is good because it tells me who to heal" but rather look at the entirety of the spell, it's full function, purpose and result.
"Using the foul sight granted by the powers of unlife" - ok...that sounds pretty darn evil. What foul powers of unlife would grant this ability to those who would use it to preserve life? Instead I would think that they would grant it to those who most want to deal death....evil people....So in this case perhaps it is not the deity blocking the good cleric from using the spell, but rather the evil powers not granting it.
The spell then goes on to describe the different levels of near death. Pretty mundane there. But the last line says that it grants the ability to see through feign death. What person in need of healing would fake being dead? Instead, this would allow an evil person to tell that someone was a faker and needed to get put over. That is the function of the last part.
After reading the spell and thinking about it, this spell is DEFINITELY a good candidate for the evil descriptor, and while does not directly do anything evil, it sure as hell is not on the good side of the fence.
I think instead of looking at spells with the [evil] descriptor and saying "My good cleric should be able to cast that spell because it has a good result" or "My good mage would have no problem casting that because I can use it for good" we should more be saying "Why is it evil and why shouldn't I use it?" I think the answer to that question is a lot easier to come up with than trying to patch something together to explain the first for each instance of the [evil] descriptor.
After looking at what I wrote, I now can without uncertainty see why this spell has the [evil] descriptor, if as I have hypothesized above the purpose of this spell is for the caster to determine the weakest person in the AoE with the intent of slaying them, then this spell is in direct support of what defines a person as evil:
“Evil” implies hurting, oppressing, and killing others.
Saying there is not fault in the spell is very similar to many arguments used by others that state the responsibility of the action lies on the shoulders of the person doing, and any ends that they use to reach this goal are not responsible, an argument I wholeheartedly disagree with. I think that responsibility does, in part, lie with the actual means and I think the [evil] descriptor in a small way tries to flag this.
Good and Evil in DnD are not like Good and Evil in the real world. In DnD Good and Evil are quantitative forces, and therefore have direct effects.