With the title, this may seem complex if you don't understand it well. We can talk from each of these ideas.
Decimal Values
Will be very interesting to have decimal values on custom variables, I think will be necessary.
Infinite Options
When you set, for example, max health, the maximum is 15. It will be awesome than maximum health and other options can get to basically any value you want. I know that with max health, health bar will be strange, but also, if the max health is higher than 15, if only shows a heart and a number with the health and the maximum health
this also will be used in: coins, lives, time, ammo, max ammo, etc.