Wall of Force (WoF)
WoF used to be such an expensive spell it hardly came up in actual practice. 10,000 GP in 1e (only shown in the DMG and not the PHB), 5,000 GP in 2e, but now just a pinch of indeterminate value from a clear gem in 3e (as far as I've seen), so I'm guessing it's going to be cast a lot more in 3e.
It also now has (D) at the end, indicating it can be dismissed by the caster at will. No longer are we plagued with the arguments if the caster's own Dispel Magic can take it down since Dispel Magic is supposed to ALWAYS work on your own magic if you wish, but the spell itself suggested Dispel Magic does not affect it at all (an apparent contradiction). Congratulations 3e for (D).
The trouble with allowing a spell effect like Ice Storm or Monster Summoning to appear outside a WoF (sphere) is this indicates some sort of viable multi planar path around the sphere. Thus, enemy spell casters could cause an Ice Storm or a Monster to appear inside your WoF (sphere) using the same path. This will hardly be acceptable, and it's not fair to have it both ways. Thus one should not be allowed to cast or summon any effect like that outside the sphere unless turn about is fair play
If WoF is a sphere, there is no path around it other than a purely astral one, like Dimension Door and Teleport employ since they operate via the astral plane. Most magic spells probably use several planes to work, not just the astral; so unless one wishes to start mapping the actual planar pathways for each spell, it's better just to assume things that can breech an enclosed WoF are very limited and on an incredibly short list.
Actual walls or hemispheres are another matter for there are multiple ways around such a thing. Over, under, and around, perhaps even through solid rock, and no total blocking barrier for spells that employ various planar pathways. Thus, if the WoF was a wall, you could cast Ice Storm and Summon Monster on the other side, just as again an enemy spell caster could similarly reach you with such things. It would still stop any spell or effect that required a clear path, however.
Line of Sight is also somehow important (this is not the same as the requirement of 'seeing' something, since fog would not really stop it anymore than fog would stop an arrow). But you certainly can't originate an Ice Storm in an enclosed room you can't even see, even if you knew it was in range just on the other side of that brick wall, even if you were scrying it (normally). Any spell would be blocked by the WoF if the blocking effect would also block a physical path, just as arrow would be blocked.
You really have to carefully read some spells and note changes from one edition to the next. Fireball seems to insists the effect starts at the caster's finger, making it like an arrow, and even 3e Lightning bolt does now too. Previous editions of Lightning Bolt didn't say this, and one could start the effect a desired distance from you, and it would continue in a straight line path away from the caster at THAT point. Thus, a WoF (curtain) could have a 2e LB originate on the other side and continue onwards, but not pass through the WoF if started too soon on the same side of the caster. 3e stops even that for LB since it, too, comes from the mage's fingers.
Remember, one of the biggest advantages of WoF is the fact it is invisible. Unless the enemy uses Spellcraft to know what you have cast, they will likely not be thinking in terms of how to get around your WoF and may uselessly expend time running into it and a few spells at you while they figure it out. That may be all the time you need.
Finally, for those who like such things, the immobile quality of the WoF must be of a nature such that it is immobile with respect to the immediate surroundings. A moving planet isn't going to leave a WoF behind in its orbit - if it did, how horrible as it ripped its way through the planet. But such a spell is devastating enough anyway, as you might cast it in the path of a large ship near its water line, for example, totally wrecking the vessel and sinking it without much effort as the wooden haul tears itself apart against the might of an immobile surface. An iceberg taking out Titanic would be as nothing compared to a ship hitting a WoF. That's why the darn thing was supposed to cost a mint to cast, but now, look out good people. It's cheap and easy
Jim
