As for your questions about logic, I look at it this way:
The Blizzard is strong enough with blowing winds, snow and such, that you can't fire out because of the effects, and for it being so damn cold. Conversely, you can't fire in because, even though you can see in for close combat, you can't see well enough to get a precise location to fire.
Spellcasting, however, is another story, being the special and spiffy lot that they are. Whether you say that they just see better, can see in another plane, or only require seeing a part of a person to target them.
Then again I have to chastise myself for committing the unforgivable sin of applying logic to a fantasy game. That can be a dangerous road to go down, due to the physical and finite nature of miniature games.
SP