It would be outstanding if implemented on devices! Some laptops from Lenovo, Asus, Dell have settings to change battery charge type. Something like "Fast Charge", "Normal" and "Battery Saver". Currently those set the charging rate and sometimes - max charge capacity. However you slice it - fast charge will degrade battery life expectancy simply by virtue of introducing more heat. If a fluctuating charge rate can potentially increase battery life expectancy then it is worth it. Most likely it could be achieved even in current laptops with smarter charge controllers. Granted no one will implement it in current products due to safety issues. But battery manufacturers should definitely look into this.