Example: A 5th level Wizard casts Fireball, and has 5 fire points. He can blow it all immediately on a single bolt for 6d6 total damage (if he hits), or a small explosion (9 squares, 4d6 damage), or large explosion (49 squares, 2d6 damage). He can also fire off one small bolt every round (2d6 damage each) for five rounds, or longer if he concentrates.
These kind of trade-offs are in Runequest's sorcery system, as well as others. They are cool in principle, but difficult to balance in practice. Even just 5 "fire points" with so many options is going to cause players to spend significant time planning/thinking/doing maths.
If we're going this route, we may as well have "Arcane Superiority" dice that get spent to augment sets of basic spells. That way, we can have less dice, and less options/maths to resolve. Instead of 5 dice at level 5, you would have just 2.
Going further - each spell could have a minimum number of dice required to cast it in combat. Any left over dice could be used to augment spells based on a "caster style".
Biggest problem with this, is it is just the (currently new and apparently popular) fighter mechanic recycled for magical skill instead of weapon skill.
I actually quite like the idea of a unified mechanic based on allocating dice from a pool. Or in fact a unifying mechanic in general for PCs. However, it might run afoul of similar problems that many have with a unified AEDU mechanic for classes - every class looks the same, nothing feels special or different enough.