Magic Attunement

Can I get an explanation as to why the "Magic Attunement" talent makes dampen/amplify magic spells weaker?

Example:
Improved Dampen magic now dampens damage taken less than the normal dampen spell. It also also makes heals slightly better. Basically this is like using a lower rank of the spell. Only its like a middle rank. Like 3.5

Is there a reason for this?

Thanks!