People have expressed concern that I'm posting suggestions mostly for clerics and that other classes should get some attention, I was doing this because arkov already proved it was doable by adding the domains he did. so I just extended the idea.
Anyway I'll post a few suggestions here for wizards and sorcerors.
One of the things people have been wanting is a way to RESEARCH spells like wizards do, normally in PnP the d.m allows this of higher level mages as it's a normal extension of their interest in magic. This results in more spells.
The idea here is to use items to simulate different spells.
The item will either activate on spells being cast on it, or it will be usable like a wand. Examining the item gives you the spell description, the item is like a page out of your spell book. The spell you cast on it would need to be the same level as (and probably a specific spell) the spell effect the item produces. The other way is to have the casting of the spell on the item recharge the item by 1 charge. Then the item can be used once.
Example: Maxi's Frost Fingers: Would be a spell that simulated frost fingers spell (a cold version of burning hands) using the visual effect of a winter wolf breath. You may need to memorise ice dagger and cast that on the item to have it happen. (or to recharge the item by one charge)
Both sorcerors and wizards would be able to use these items, (sorcerors would be able to pick at level up from some TEACHER (ie vendor) of these items and there may also well be bard specific items too.
Counterspelling these spells would be very hard to implement, but possibly you could do it by having a portion of casting animation that is counterable BEFORE the item effect happens.
An extremely hard system to implement though, it would allow for custom spells in a non-hakpack environment. The spells would be designed and implemented by d.m's though a higher level mage may be allowed to roleplay the research needed for it to happen. (and get their name on the spell)