Has anyone played sacred 2 ? It has a very good system for spells enhancement : you can choose up to 3 upgrades for your spells. And som eupgrades are mutually exclusive, so you have to make a choice.
In Elemental we could have enhancement based on shards you own. For instance in the research spells, instead or buying a new spell you can use your psell points to upgrade a spell IF you have the necesseray shards.
For instance : You have the fireball and you control one shard. You research an upgrade that allow you to have an area of effect on your fireball. It has a cost in spell points, and you can only use as many spell points per turn as your number of shards. If the AoE is 50 spell points, you would need 50 turns if you have a fire shard, 25 turns if you have 2 fire shards, etc.
Or .. in battle you can enhance the spells you throw thanks to shards : when you choose your fireball you have options. If you have 1 fire shard you get the possibility to enhance damage but at a greater cost in mana. If you have 2 fire shards you have two options : more damage or a small area of effect, three shards you can combine the first two options, 4 fire shards, you can combine them for less mana increase, or choose only one enhancment for no mana increase, etc.