I don't know if something like this has already been suggested and discounted then I apologise. 

I'm proposing a new talisman accessory to alter a champions base stats. Basically you'd have the option to suppress the value of   attribute and allocate it to another. The idea being that you can tweak and balance a team easier or boost an attribute if your short (possibly for crit). Not all stats scale equally so I would suggest that a single tali-point might equal 20 health/defence and possibly 15 attack or 2 speed etc. So,  if you took off 2 points in speed then you might get to add 20 points to your health. 

Like artifacts in the game if a talisman dropped it would be allocated the attributes it affects at random an the rarity dictates to number and the degree that the attributes could be altered. 

For example 

A common option to suppress 1 attribute only 

An uncommon would have 2 attributes with which you could suppress 1 and raise the other.

A rare would have 3 attributes with 2 turns to alter the attributes. So you could take 2 off 1 and add to the others or vica versa 

Etc etc

This was really difficult to type on my phone for some reason. Hope it makes sense. 

Any thoughts?