Sir Whiskers said:
2) Vancian magic makes these spellcasters more difficult for new players. These players have little, if any, information on which to base their choice of spells. So what ends up happening is that the GM or another, more experienced, player tells them what to memorize - which smacks too much of telling these players how to play their character.
As opposed to overwhelming them in the heat of battle with every spell at their disposal at which point the GM or another, more experienced, player tells them what to cast? Or worse, everybody discusses what should be cast, bringing play to a grinding halt. (This would be why I usually suggest fighters or rogues for new players.) New players will always want/need advice from more experienced players, that's just the way it goes. And, when you give advice, you can either say, "Take this, this, and this. Then cast them under these conditions.", or you can ask, "What sorts of things to you want to do with your spells? If you are most conserned with this, then these spells are good for that. And these other spells are good for this sort of thing..." I favor the latter type of advice, but any way you slice it, how more experienced players give advice is a more personal sort of thing that won't be changed no matter what the mechanic for casting your spells is.
I don't know about anybody else, but the whole having to pray/memorize thing only comes into play when we decide who takes which watch.
In my opinion, having to select which spells you're going to be able to cast that day is a fine trade off for a more powerful and varied selection of spells.
As far as I can tell, the changes mentioned above are already in play with the core Sorcerer, the core Bard, and the "Favored Soul" class in the miniatures handbook. (Which is a spontaneously casting cleric.)