Last day, somebody in marketplace (chaos) had an idea about rating based equipments. I worked out this idea and came on special Prestige school items..
for example:
Maul of the Battlemage
req: (Btlm),rating (120)
bonus:
All (or some) abilities from his base schools mastered.
When a battlemage reaches rating 120 it can wear this maul
to master multicast for instance.
There should be a timeout on the equip/unequip of the item.
This way, presige classes are more prestige and its fun to collect your class based items.