TLDR: I want to make all Wizards use Word Magic so the class becomes about designing spells. What say you?!
So I've been an avid Pathfinder player since I first heard about the Beta way back, but I've only been GMing for about a year. I'm a younger person so my 3.5 DMing experience wasn't really as an adult, and I'm still learning the ropes. That being said I've discovered very quickly that I prefer to accompany my own world with some unique rules. Examples of these include: I don't let good players use Summon Monster spells, I require rangers to use the "Skirmisher" features, I don't allow Inquisitors. These may seam extreme, but they were all worked out WITH my players as we explored the world together. The Skirmisher requirement for example, was suggested by a player who wanted to play a Skirmisher and felt they fit better into my world since the setting is somewhat low magic. Obviously there are exceptions to all these rules at times. If a Ranger has a good excuse for knowing magic of course she can use spells! Sometimes a spellcaster will need to summon creatures from the planes to save the day even though it's forbidden by the gods.
I've started work on a document that contains all of my campaign setting's special rules so that I can let players come up with new characters easier, and get newer players up to speed. This includes everything from the background of certain races and kingdoms, to each class's specific alterations, and even a list of feats that I approve of from all books (I know it's bad form to cherry pick instead of just opening up books for use, but I've seen too many broken spellcasters in my day). Right now I'm just hashing out a few of the last rules.
My biggest problem is the Wizard. This setting is low magic (as least relatively), and while I'm content to simply limit upper level spells (6+) for other casters, this seams to nerf the Wizard a bit too much. Their whole schtick is having a wide variety of spells known, and versatility with those spells. My idea, which I have not tested, is to make all Wizards Wordcasters. I like the concept that the Wizard is a true student of magic, and is the only class capable of designing his own spells. Other classes are limited by tradition, but the Wizard is a magical scientist. Does anyone have experience with Word Magic, and if so how do you think this would work out? Are there changes I would need to make? Just so you know, the other classes I allow to cast spells are: Alchemists, Bards, Clerics, Druids, Oracles, Paladins, Sorcerers, and Witches.