El-remmen: Good ideas.
el-remmen said:
Limit the number of spells wizards learn as they advance in level (1 every 2 levels instead of 2 every 1 level)
In my own campaign for many years, I've simply ruled that you don't gain any new spells automatically as you level. I started doing this when I elimenated mandatory training (and the associated fees) when you wanted to level. If you want spells, you have to find them in some fashion. Now, I tend to be pretty generous about including spell books as part of the treasure, so its not like the player is suffering for spells necessarily, but it does mean that every spell that they may want is not immediately available.
Giving each priesthood its own custom spell list
I haven't gone that far, but I do tend to think that you either need to do that, or else have spells known for clerics, or else limit clerics to core spells only. Otherwise, the flexibility that clerics attain is just too great.
Required training for certain class abilities, feat and skills
I find that this ends up punishing me as a DM more than it helps me. I don't really want the story to be interrupted regularly by long periods of down time. A period like that every few levels is ok, but not desirable in all cases.
Magical item creation requires power components and special "recipes" - when you learn an item creation feat you are learning how to make something specific - which then can be applied to create other things with more research/time (this applie mostly to wonderous items, rings, staves)
I use to do that for 1st edition, but it was tedious work as a DM. On the other hand, it meant that recipes could be found as (highly desirable) treasure. I haven't reintroduced the idea of recipes since 3rd edition, but I have been toying with the idea.
Certain kinds of magical items can only be made by certain magic types (i.e. wands are only arcane)
Yoink. That is a great idea.
Base Defense that improves AC for all classes as they advance (depending on class) to make up for lack of magic armor
Something that I've been toying with doing, but I'm worried about how it will effect balance since eventually the magic armor will arrive in some form. How is it working out for you?
A general reinforcement of the setting's view on magic. both in terms of character background, but the consequences of public abuse of magic
This ought to be an important consideration in any campaign setting, whether high magic or low magic. In fact, there are very few settings where I think that enough consideration has been given to the consequences of magic and how it would shape society. I'm not a big of Eberron, but one thing I do like about it is that it does seem like the creator did think long and hard about this subject. Someone who wants to take magic in the other direction ought to think equally long and hard.